how to write a systematic review protocol

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Systematic reviews.

• Should I do a systematic review?
• Writing the Protocol
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How do I write a protocol?

The protocol serves as a roadmap for your review and specifies the objectives, methods, and outcomes of primary interest of the systematic review. Having a protocol promotes transparency and can be helpful for project management. Some journals require you to submit your protocol along with your manuscript. 

A good way to familiarize yourself with research protocols is to take a look at those registered on PROSPERO. PROSPERO's registration form includes 22 mandatory fields and 18 optional fields which will help you to explain every aspect of your research plan. 

• PROSPERO - International prospective register of systematic reviews

A protocol ideally includes the following:

• Databases to be searched and additional sources (particularly for grey literature)
• Keywords to be used in the search strategy
• Limits applied to the search
• Screening process
• Data to be extracted
• Summary of data to be reported

Once you have written your protocol, it is advisable to register it. Registering your protocol is a good way to announce that you are working on a review, so that others do not start working on it.

The University of Warwick's protocol template is available below and is a great tool for planning your protocol. 

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Example Protocols

Living systematic review.

Carole Mitnick, Molly Franke, Celia Fung, Andrew Lindeborg. Clinical Outcomes of Individuals with COVID-19 and Tuberculosis Disease: a Living Systematic Review . PROSPERO 2020 CRD42020187349 

Systematic Review and Meta-Analysis

Brindle ME, Roberts DJ, Daodu O, Haynes AB, Cauley C, Dixon E, La Flamme C, Bain P, Berry W. Deriving literature-based benchmarks for surgical complications in high-income countries: a protocol for a systematic review and meta-analysis. BMJ Open. 2017 May 9. PMID: 28487456

Why a protocol?

A protocol is your plan for carrying out your knowledge synthesis. It presents the rationale for carrying out the project and clearly states the aims of the work. The protocol describes the process for selecting research for inclusion, including the provision of explicit criteria for assessing reports for inclusion and for analyzing the included reports. Hence, it is an internal document that helps team members work together more smoothly. But it also is a hedge against bias by clearly stating the rules of the game before any work has begun. A protocol makes it more difficult to alter selection patterns based on perceived results. Beyond acting as a roadmap for your research, protocols, when registered or published in some way, allow others to see your research plan, establishing priority and reducing the risk of duplicate research.

We require a completed protocol before we will carry out final searches on any knowledge synthesis project. We encourage you to use this template, which is based on the PRISMA-P checklist (Moher D, et al. Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) 2015 statement. Syst Rev. 2015;4(1):1. PMID: 25554246 .)

• Countway Protocol Template
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Systematic Review

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   • PRISMA Flow Diagram  - Record the numbers of retrieved references and included/excluded studies

   •  PRISMA Checklist - Checklist of items to include when reporting a systematic review or meta-analysis

PRISMA 2020 and PRISMA-S: Common Questions on Tracking Records and the Flow Diagram

• PROSPERO Template
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Adapted from  A Guide to Conducting Systematic Reviews: Steps in a Systematic Review by Cornell University Library

Source: Cochrane Consumers and Communications  (infographics are free to use and licensed under Creative Commons )

Check the following visual resources titled " What Are Systematic Reviews?"

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Article Contents

Introduction, contents of a systematic review/meta-analysis protocol, conflict of interest statement.

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How to write a systematic review or meta-analysis protocol

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Julien Al Shakarchi, How to write a systematic review or meta-analysis protocol, Journal of Surgical Protocols and Research Methodologies , Volume 2022, Issue 3, July 2022, snac015, https://doi.org/10.1093/jsprm/snac015

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A protocol is an important document that specifies the research plan for a systematic review/meta analysis. In this paper, we have explained a simple and clear approach to writing a research study protocol for a systematic review or meta-analysis.

A study protocol is an essential part of any research project. It sets out in detail the research methodology to be used for the systematic review or meta-analysis. It assists the research team to stay focused on the question to be answered by the study. Prospero, from the Centre for Reviews and Dissemination at the University of York, is an international prospective register of systematic reviews and authors should consider registering their research to reduce the potential for duplication of work. In this paper, we will explain how to write a research protocol by describing what needs to be included.

Introduction

This section sets out the need for the planned research and the context of the current evidence. It should be supported by an extensive background to the topic with appropriate references to the literature. This should be followed by a brief description of the condition and the target population. A clear explanation for the rationale and objective of the project is also expected to justify the need of the study.

Methods and analysis

A detailed search strategy is necessary to be described in the protocol. It should set out which databases are to be included as well as the specific keywords be searched and publication timeframe. The inclusion/exclusion criteria should be described for the type of studies, participants and interventions. The population, intervention, comparator and outcome (PICO) framework is a useful tool to consider for this section.

The methodology of the data extraction should be detailed in this section and should include how many reviewers will be involved and how any disagreement will be resolved. The methodology to be used for quality and bias assessment of included studies should also be described in this section. Data analysis including statistical methodology needs to be established clearly in this section of the protocol. Finally details of any planned subgroup analyses should also be included.

Ethics and dissemination

Any competing interests of the researchers should also be stated in this section. The authorship of any publication should have a clear and fair criterion which should be described in this section of the protocol. By doing so, it will resolve any issues arising at the publication stage.

Funding statement

It is important to explain who are the sponsors and funders of the study. It should clearly clarify the involvement and potential influence of any party. The protocol should explicitly outline the roles and responsibilities of any funder(s) in study design, data analysis and interpretation, manuscript writing and dissemination of results.

A protocol is an important document that specifies the research plan for a systematic review or meta-analysis. It should be written in detail and researchers should aim to publish their study protocols. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement provides a useful checklist on what should be included in a systematic review [ 1 ]. In this paper, we have explained a simple and clear approach to writing a research study protocol for a systematic review or meta-analysis.

None declared.

Page   MJ , McKenzie   JE , Bossuyt   PM , Boutron   I , Hoffmann   TC , Mulrow   CD , et al.    The PRISMA 2020 statement: an updated guideline for reporting systematic reviews . BMJ   2021 ; 372 : n71 .

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The Whats and Whys of Protocols

Systematic reviews and scoping reviews should have a protocol which helps to plan and outline the study methodology. The protocol should include:

• the rationale for the review
• key questions broken into PICO (or other structured research question) components
• inclusion/exclusion criteria
• literature searches for published/unpublished literature
• data abstraction/data management
• assessment of methodological quality/risk of bias of individual studies (not required for scoping reviews)
• data synthesis
• grading the evidence for each key question

Why should complete a protocol?

• A protocol is your planning document and roadmap for the project. It allows you to complete a systematic review efficiently and accurately, ensures greater understanding among team members, and makes writing the manuscript far easier.
• Many journals now require submitted systematic reviews to have registered protocols.
• The PRISMA Reporting Standard lists information about the systematic review protocol as an "essential element" (PRISMA 2020 Item 24)
• The Cochrane Handbook, The Institute of Medicine Standards, and others, all list completing a protocol as one of the important steps to a successful systematic review.
• Best practices in systematic reviews: the importance of protocols & registration
• Planning a systematic review? Think protocols

Writing a Protocol

Protocol templates:

• PRISMA for systematic review protocols (PRISMA-P) Checklist and explanation of what should be included in a systematic review protocol.
• The PROSPERO systematic review protocol template
• OSF Scoping Review Protocol Template and Guidance Document "The Guidance document is intended to be used in tandem with the Scoping Review Protocol Template. The Guidance document includes tips, examples, and details about each section of the protocol. The Template includes headings and subheadings to use to structure the protocol (e.g., which order to present the information, what level of detail, etc.).”
• JBI scoping review protocol template

Resources to help authors prepare a protocol for a systematic or scoping review:

• Institute of Medicine – Standards for Systematic Reviews - Section 2.6
• The Cochrane Handbook - Section ii.1.4
• JBI Manual for Evidence Synthesis - Section 1.3 (Systematic reviews) & 11.2 (Scoping reviews)

Where to Register a Protocol

After you write the protocol, you should register it with a review registry. There are numerous review registries available, such as PROSPERO or OSF. Registration is free and open to anyone undertaking systematic reviews. Some journals also publish systematic review protocols.

• PROSPERO A registry for systematic review protocols
• How to register with PROSPERO

OSF can be used to pre-register a systematic or scoping review protocol and to share documents such as a citation management library, search strategies, and data extraction forms. Unlike other registries, evidence synthesis author teams do not submit their protocols for review by an editorial board before they are accepted and pre-registered on OSF. Instead, create your own pre-registration.

• How to create an OSF registration
• OSF Registrations Form

Scoping reviews may not be registered with PROSPERO.  Currently, they can be registered with the Open Science Framework or Figshare.

Publishing a Protocol

• BioMed Central Protocols BioMed Central will consider protocols of any type of research for publication, following the standard peer review.
• BMJ Open BMJ Open "will consider publishing without peer review protocols that have formal ethical approval and funding from a recognized, open access advocating research-funding body". Otherwise, protocols are peer reviewed.
• JBI Evidence Synthesis Like systematic reviews, scoping review protocols can be published in some journals.
• Systematic Reviews, a BioMed Central journal This open access title publishes protocols of systematic reviews broadly related to health sciences.
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Cochrane Training

Chapter 1: starting a review.

Toby J Lasserson, James Thomas, Julian PT Higgins

Key Points:

• Systematic reviews address a need for health decision makers to be able to access high quality, relevant, accessible and up-to-date information.
• Systematic reviews aim to minimize bias through the use of pre-specified research questions and methods that are documented in protocols, and by basing their findings on reliable research.
• Systematic reviews should be conducted by a team that includes domain expertise and methodological expertise, who are free of potential conflicts of interest.
• People who might make – or be affected by – decisions around the use of interventions should be involved in important decisions about the review.
• Good data management, project management and quality assurance mechanisms are essential for the completion of a successful systematic review.

Cite this chapter as: Lasserson TJ, Thomas J, Higgins JPT. Chapter 1: Starting a review. In: Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.4 (updated August 2023). Cochrane, 2023. Available from www.training.cochrane.org/handbook .

1.1 Why do a systematic review?

Systematic reviews were developed out of a need to ensure that decisions affecting people’s lives can be informed by an up-to-date and complete understanding of the relevant research evidence. With the volume of research literature growing at an ever-increasing rate, it is impossible for individual decision makers to assess this vast quantity of primary research to enable them to make the most appropriate healthcare decisions that do more good than harm. By systematically assessing this primary research, systematic reviews aim to provide an up-to-date summary of the state of research knowledge on an intervention, diagnostic test, prognostic factor or other health or healthcare topic. Systematic reviews address the main problem with ad hoc searching and selection of research, namely that of bias. Just as primary research studies use methods to avoid bias, so should summaries and syntheses of that research.

A systematic review attempts to collate all the empirical evidence that fits pre-specified eligibility criteria in order to answer a specific research question. It uses explicit, systematic methods that are selected with a view to minimizing bias, thus providing more reliable findings from which conclusions can be drawn and decisions made (Antman et al 1992, Oxman and Guyatt 1993). Systematic review methodology, pioneered and developed by Cochrane, sets out a highly structured, transparent and reproducible methodology (Chandler and Hopewell 2013). This involves: the a priori specification of a research question; clarity on the scope of the review and which studies are eligible for inclusion; making every effort to find all relevant research and to ensure that issues of bias in included studies are accounted for; and analysing the included studies in order to draw conclusions based on all the identified research in an impartial and objective way.

This Handbook is about systematic reviews on the effects of interventions, and specifically about methods used by Cochrane to undertake them. Cochrane Reviews use primary research to generate new knowledge about the effects of an intervention (or interventions) used in clinical, public health or policy settings. They aim to provide users with a balanced summary of the potential benefits and harms of interventions and give an indication of how certain they can be of the findings. They can also compare the effectiveness of different interventions with one another and so help users to choose the most appropriate intervention in particular situations. The primary purpose of Cochrane Reviews is therefore to inform people making decisions about health or health care.

Systematic reviews are important for other reasons. New research should be designed or commissioned only if it does not unnecessarily duplicate existing research (Chalmers et al 2014). Therefore, a systematic review should typically be undertaken before embarking on new primary research. Such a review will identify current and ongoing studies, as well as indicate where specific gaps in knowledge exist, or evidence is lacking; for example, where existing studies have not used outcomes that are important to users of research (Macleod et al 2014). A systematic review may also reveal limitations in the conduct of previous studies that might be addressed in the new study or studies.

Systematic reviews are important, often rewarding and, at times, exciting research projects. They offer the opportunity for authors to make authoritative statements about the extent of human knowledge in important areas and to identify priorities for further research. They sometimes cover issues high on the political agenda and receive attention from the media. Conducting research with these impacts is not without its challenges, however, and completing a high-quality systematic review is often demanding and time-consuming. In this chapter we introduce some of the key considerations for potential review authors who are about to start a systematic review.

1.2 What is the review question?

Getting the research question right is critical for the success of a systematic review. Review authors should ensure that the review addresses an important question to those who are expected to use and act upon its conclusions.

We discuss the formulation of questions in detail in Chapter 2 . For a question about the effects of an intervention, the PICO approach is usually used, which is an acronym for Population, Intervention, Comparison(s) and Outcome. Reviews may have additional questions, for example about how interventions were implemented, economic issues, equity issues or patient experience.

To ensure that the review addresses a relevant question in a way that benefits users, it is important to ensure wide input. In most cases, question formulation should therefore be informed by people with various relevant – but potentially different – perspectives (see Chapter 2, Section 2.4 ).

1.3 Who should do a systematic review?

Systematic reviews should be undertaken by a team. Indeed, Cochrane will not publish a review that is proposed to be undertaken by a single person. Working as a team not only spreads the effort, but ensures that tasks such as the selection of studies for eligibility, data extraction and rating the certainty of the evidence will be performed by at least two people independently, minimizing the likelihood of errors. First-time review authors are encouraged to work with others who are experienced in the process of systematic reviews and to attend relevant training.

Review teams must include expertise in the topic area under review. Topic expertise should not be overly narrow, to ensure that all relevant perspectives are considered. Perspectives from different disciplines can help to avoid assumptions or terminology stemming from an over-reliance on a single discipline. Review teams should also include expertise in systematic review methodology, including statistical expertise.

Arguments have been made that methodological expertise is sufficient to perform a review, and that content expertise should be avoided because of the risk of preconceptions about the effects of interventions (Gøtzsche and Ioannidis 2012). However, it is important that both topic and methodological expertise is present to ensure a good mix of skills, knowledge and objectivity, because topic expertise provides important insight into the implementation of the intervention(s), the nature of the condition being treated or prevented, the relationships between outcomes measured, and other factors that may have an impact on decision making.

A Cochrane Review should represent an independent assessment of the evidence and avoiding financial and non-financial conflicts of interest often requires careful management. It will be important to consider if there are any relevant interests that may constitute a conflict of interest. There are situations where employment, holding of patents and other financial support should prevent people joining an author team. Funding of Cochrane Reviews by commercial organizations with an interest in the outcome of the review is not permitted. To ensure that any issues are identified early in the process, authors planning Cochrane Reviews should consult the Conflict of Interest Policy . Authors should make complete declarations of interest before registration of the review, and refresh these annually thereafter until publication and just prior to publication of the protocol and the review. For authors of review updates, this must be done at the time of the decision to update the review, annually thereafter until publication, and just prior to publication. Authors should also update declarations of interest at any point when their circumstances change.

1.3.1 Involving consumers and other stakeholders

Because the priorities of decision makers and consumers may be different from those of researchers, it is important that review authors consider carefully what questions are important to these different stakeholders. Systematic reviews are more likely to be relevant to a broad range of end users if they are informed by the involvement of people with a range of experiences, in terms of both the topic and the methodology (Thomas et al 2004, Rees and Oliver 2017). Engaging consumers and other stakeholders, such as policy makers, research funders and healthcare professionals, increases relevance, promotes mutual learning, improved uptake and decreases research waste.

Mapping out all potential stakeholders specific to the review question is a helpful first step to considering who might be invited to be involved in a review. Stakeholders typically include: patients and consumers; consumer advocates; policy makers and other public officials; guideline developers; professional organizations; researchers; funders of health services and research; healthcare practitioners, and, on occasion, journalists and other media professionals. Balancing seniority, credibility within the given field, and diversity should be considered. Review authors should also take account of the needs of resource-poor countries and regions in the review process (see Chapter 16 ) and invite appropriate input on the scope of the review and the questions it will address.

It is established good practice to ensure that consumers are involved and engaged in health research, including systematic reviews. Cochrane uses the term ‘consumers’ to refer to a wide range of people, including patients or people with personal experience of a healthcare condition, carers and family members, representatives of patients and carers, service users and members of the public. In 2017, a Statement of Principles for consumer involvement in Cochrane was agreed. This seeks to change the culture of research practice to one where both consumers and other stakeholders are joint partners in research from planning, conduct, and reporting to dissemination. Systematic reviews that have had consumer involvement should be more directly applicable to decision makers than those that have not (see online Chapter II ).

1.3.2 Working with consumers and other stakeholders

Methods for working with consumers and other stakeholders include surveys, workshops, focus groups and involvement in advisory groups. Decisions about what methods to use will typically be based on resource availability, but review teams should be aware of the merits and limitations of such methods. Authors will need to decide who to involve and how to provide adequate support for their involvement. This can include financial reimbursement, the provision of training, and stating clearly expectations of involvement, possibly in the form of terms of reference.

While a small number of consumers or other stakeholders may be part of the review team and become co-authors of the subsequent review, it is sometimes important to bring in a wider range of perspectives and to recognize that not everyone has the capacity or interest in becoming an author. Advisory groups offer a convenient approach to involving consumers and other relevant stakeholders, especially for topics in which opinions differ. Important points to ensure successful involvement include the following.

• The review team should co-ordinate the input of the advisory group to inform key review decisions.
• The advisory group’s input should continue throughout the systematic review process to ensure relevance of the review to end users is maintained.
• Advisory group membership should reflect the breadth of the review question, and consideration should be given to involving vulnerable and marginalized people (Steel 2004) to ensure that conclusions on the value of the interventions are well-informed and applicable to all groups in society (see Chapter 16 ).

Templates such as terms of reference, job descriptions, or person specifications for an advisory group help to ensure clarity about the task(s) required and are available from INVOLVE . The website also gives further information on setting and organizing advisory groups. See also the Cochrane training website for further resources to support consumer involvement.

1.4 The importance of reliability

Systematic reviews aim to be an accurate representation of the current state of knowledge about a given issue. As understanding improves, the review can be updated. Nevertheless, it is important that the review itself is accurate at the time of publication. There are two main reasons for this imperative for accuracy. First, health decisions that affect people’s lives are increasingly taken based on systematic review findings. Current knowledge may be imperfect, but decisions will be better informed when taken in the light of the best of current knowledge. Second, systematic reviews form a critical component of legal and regulatory frameworks; for example, drug licensing or insurance coverage. Here, systematic reviews also need to hold up as auditable processes for legal examination. As systematic reviews need to be both correct, and be seen to be correct, detailed evidence-based methods have been developed to guide review authors as to the most appropriate procedures to follow, and what information to include in their reports to aid auditability.

1.4.1 Expectations for the conduct and reporting of Cochrane Reviews

Cochrane has developed methodological expectations for the conduct, reporting and updating of systematic reviews of interventions (MECIR) and their plain language summaries ( Plain Language Expectations for Authors of Cochrane Summaries ; PLEACS). Developed collaboratively by methodologists and Cochrane editors, they are intended to describe the desirable attributes of a Cochrane Review. The expectations are not all relevant at the same stage of review conduct, so care should be taken to identify those that are relevant at specific points during the review. Different methods should be used at different stages of the review in terms of the planning, conduct, reporting and updating of the review.

Each expectation has a title, a rationale and an elaboration. For the purposes of publication of a review with Cochrane, each has the status of either ‘mandatory’ or ‘highly desirable’. Items described as mandatory are expected to be applied, and if they are not then an appropriate justification should be provided; failure to implement such items may be used as a basis for deciding not to publish a review in the Cochrane Database of Systematic Reviews (CDSR). Items described as highly desirable should generally be implemented, but there are reasonable exceptions and justifications are not required.

All MECIR expectations for the conduct of a review are presented in the relevant chapters of this Handbook . Expectations for reporting of completed reviews (including PLEACS) are described in online Chapter III . The recommendations provided in the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) Statement have been incorporated into the Cochrane reporting expectations, ensuring compliance with the PRISMA recommendations and summarizing attributes of reporting that should allow a full assessment of the methods and findings of the review (Moher et al 2009).

1.5 Protocol development

Preparing a systematic review is complex and involves many judgements. To minimize the potential for bias in the review process, these judgements should be made as far as possible in ways that do not depend on the findings of the studies included in the review. Review authors’ prior knowledge of the evidence may, for example, influence the definition of a systematic review question, the choice of criteria for study eligibility, or the pre-specification of intervention comparisons and outcomes to analyse. It is important that the methods to be used should be established and documented in advance (see MECIR Box 1.5.a , MECIR Box 1.5.b and MECIR Box 1.5.c ).

Publication of a protocol for a review that is written without knowledge of the available studies reduces the impact of review authors’ biases, promotes transparency of methods and processes, reduces the potential for duplication, allows peer review of the planned methods before they have been completed, and offers an opportunity for the review team to plan resources and logistics for undertaking the review itself. All chapters in the Handbook should be consulted when drafting the protocol. Since systematic reviews are by their nature retrospective, an element of knowledge of the evidence is often inevitable. This is one reason why non-content experts such as methodologists should be part of the review team (see Section 1.3 ). Two exceptions to the retrospective nature of a systematic review are a meta-analysis of a prospectively planned series of trials and some living systematic reviews, as described in Chapter 22 .

The review question should determine the methods used in the review, and not vice versa. The question may concern a relatively straightforward comparison of one treatment with another; or it may necessitate plans to compare different treatments as part of a network meta-analysis, or assess differential effects of an intervention in different populations or delivered in different ways.

The protocol sets out the context in which the review is being conducted. It presents an opportunity to develop ideas that are foundational for the review. This concerns, most explicitly, definition of the eligibility criteria such as the study participants and the choice of comparators and outcomes. The eligibility criteria may also be defined following the development of a logic model (or an articulation of the aspects of an extent logic model that the review is addressing) to explain how the intervention might work (see Chapter 2, Section 2.5.1 ).

MECIR Box 1.5.a Relevant expectations for conduct of intervention reviews

A key purpose of the protocol is to make plans to minimize bias in the eventual findings of the review. Reliable synthesis of available evidence requires a planned, systematic approach. Threats to the validity of systematic reviews can come from the studies they include or the process by which reviews are conducted. Biases within the studies can arise from the method by which participants are allocated to the intervention groups, awareness of intervention group assignment, and the collection, analysis and reporting of data. Methods for examining these issues should be specified in the protocol. Review processes can generate bias through a failure to identify an unbiased (and preferably complete) set of studies, and poor quality assurance throughout the review. The availability of research may be influenced by the nature of the results (i.e. reporting bias). To reduce the impact of this form of bias, searching may need to include unpublished sources of evidence (Dwan et al 2013) ( MECIR Box 1.5.b ).

MECIR Box 1.5.b Relevant expectations for the conduct of intervention reviews

Developing a protocol for a systematic review has benefits beyond reducing bias. Investing effort in designing a systematic review will make the process more manageable and help to inform key priorities for the review. Defining the question, referring to it throughout, and using appropriate methods to address the question focuses the analysis and reporting, ensuring the review is most likely to inform treatment decisions for funders, policy makers, healthcare professionals and consumers. Details of the planned analyses, including investigations of variability across studies, should be specified in the protocol, along with methods for interpreting the results through the systematic consideration of factors that affect confidence in estimates of intervention effect ( MECIR Box 1.5.c ).

MECIR Box 1.5.c Relevant expectations for conduct of intervention reviews

While the intention should be that a review will adhere to the published protocol, changes in a review protocol are sometimes necessary. This is also the case for a protocol for a randomized trial, which must sometimes be changed to adapt to unanticipated circumstances such as problems with participant recruitment, data collection or event rates. While every effort should be made to adhere to a predetermined protocol, this is not always possible or appropriate. It is important, however, that changes in the protocol should not be made based on how they affect the outcome of the research study, whether it is a randomized trial or a systematic review. Post hoc decisions made when the impact on the results of the research is known, such as excluding selected studies from a systematic review, or changing the statistical analysis, are highly susceptible to bias and should therefore be avoided unless there are reasonable grounds for doing this.

Enabling access to a protocol through publication (all Cochrane Protocols are published in the CDSR ) and registration on the PROSPERO register of systematic reviews reduces duplication of effort, research waste, and promotes accountability. Changes to the methods outlined in the protocol should be transparently declared.

This Handbook provides details of the systematic review methods developed or selected by Cochrane. They are intended to address the need for rigour, comprehensiveness and transparency in preparing a Cochrane systematic review. All relevant chapters – including those describing procedures to be followed in the later stages of the review – should be consulted during the preparation of the protocol. A more specific description of the structure of Cochrane Protocols is provide in online Chapter II .

1.6 Data management and quality assurance

Systematic reviews should be replicable, and retaining a record of the inclusion decisions, data collection, transformations or adjustment of data will help to establish a secure and retrievable audit trail. They can be operationally complex projects, often involving large research teams operating in different sites across the world. Good data management processes are essential to ensure that data are not inadvertently lost, facilitating the identification and correction of errors and supporting future efforts to update and maintain the review. Transparent reporting of review decisions enables readers to assess the reliability of the review for themselves.

Review management software, such as Covidence and EPPI-Reviewer , can be used to assist data management and maintain consistent and standardized records of decisions made throughout the review. These tools offer a central repository for review data that can be accessed remotely throughout the world by members of the review team. They record independent assessment of studies for inclusion, risk of bias and extraction of data, enabling checks to be made later in the process if needed. Research has shown that even experienced reviewers make mistakes and disagree with one another on risk-of-bias assessments, so it is particularly important to maintain quality assurance here, despite its cost in terms of author time. As more sophisticated information technology tools begin to be deployed in reviews (see Chapter 4, Section 4.6.6.2 and Chapter 22, Section 22.2.4 ), it is increasingly apparent that all review data – including the initial decisions about study eligibility – have value beyond the scope of the individual review. For example, review updates can be made more efficient through (semi-) automation when data from the original review are available for machine learning.

1.7 Chapter information

Authors: Toby J Lasserson, James Thomas, Julian PT Higgins

Acknowledgements: This chapter builds on earlier versions of the Handbook . We would like to thank Ruth Foxlee, Richard Morley, Soumyadeep Bhaumik, Mona Nasser, Dan Fox and Sally Crowe for their contributions to Section 1.3 .

Funding: JT is supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care North Thames at Barts Health NHS Trust. JPTH is a member of the NIHR Biomedical Research Centre at University Hospitals Bristol NHS Foundation Trust and the University of Bristol. JPTH received funding from National Institute for Health Research Senior Investigator award NF-SI-0617-10145. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.

1.8 References

Antman E, Lau J, Kupelnick B, Mosteller F, Chalmers T. A comparison of results of meta-analyses of randomized control trials and recommendations of clinical experts: treatment for myocardial infarction. JAMA 1992; 268 : 240–248.

Chalmers I, Bracken MB, Djulbegovic B, Garattini S, Grant J, Gulmezoglu AM, Howells DW, Ioannidis JP, Oliver S. How to increase value and reduce waste when research priorities are set. Lancet 2014; 383 : 156–165.

Chandler J, Hopewell S. Cochrane methods – twenty years experience in developing systematic review methods. Systematic Reviews 2013; 2 : 76.

Dwan K, Gamble C, Williamson PR, Kirkham JJ, Reporting Bias Group. Systematic review of the empirical evidence of study publication bias and outcome reporting bias: an updated review. PloS One 2013; 8 : e66844.

Gøtzsche PC, Ioannidis JPA. Content area experts as authors: helpful or harmful for systematic reviews and meta-analyses? BMJ 2012; 345 .

Macleod MR, Michie S, Roberts I, Dirnagl U, Chalmers I, Ioannidis JP, Al-Shahi Salman R, Chan AW, Glasziou P. Biomedical research: increasing value, reducing waste. Lancet 2014; 383 : 101–104.

Moher D, Liberati A, Tetzlaff J, Altman D, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Medicine 2009; 6 : e1000097.

Oxman A, Guyatt G. The science of reviewing research. Annals of the New York Academy of Sciences 1993; 703 : 125–133.

Rees R, Oliver S. Stakeholder perspectives and participation in reviews. In: Gough D, Oliver S, Thomas J, editors. An Introduction to Systematic Reviews . 2nd ed. London: Sage; 2017. p. 17–34.

Steel R. Involving marginalised and vulnerable people in research: a consultation document (2nd revision). INVOLVE; 2004.

Thomas J, Harden A, Oakley A, Oliver S, Sutcliffe K, Rees R, Brunton G, Kavanagh J. Integrating qualitative research with trials in systematic reviews. BMJ 2004; 328 : 1010–1012.

For permission to re-use material from the Handbook (either academic or commercial), please see here for full details.

Systematic Reviews

• Introduction
• Review Process: Step by Step
• 1. Planning a Review
• 2. Defining Your Question & Criteria

Why Use Protocols?

Developing your protocol, registering your protocol, protocol standards, reporting standards.

• 4. Search Terms & Strategies
• 5. Locating Published Research
• 6. Locating Grey Literature
• 7. Managing & Documenting Results
• 8. Selecting & Appraising Studies
• 9. Extracting Data
• 10. Writing a Systematic Review
• Tools & Software
• Guides & Tutorials
• Accessing Resources
• Research Assistance

A systematic review protocol describes in detail, the rationale, hypothesis, and methodology of the review. Your protocol should be prepared before a review is started and used as a guide to carry out the review.

A protocol helps to  ensure that published systematic reviews are clear, transparent, accurate, and fully replicable. Researcher institutions and organizations have developed sets of standards for systematic review publication; you may be required to use a specific set of standards however reviewing commonly used standards can assist in the development of your own protocol. 

Reporting standards, such as PRISMA, are standards for reporting your process and findings when writing your review.

Developing a protocol before you begin will help you plan how you'll conduct your systematic review. Many of the elements in the protocol will also be used in your final article. Your protocol should specify:

• The rationale for your systematic review.
• Project timeline.
• Your research question in detail (PICO, study design, setting, time-frame).
• Anticipated search terms, search strategies, and databases,
• The information sources you'll search.
• The inclusion/exclusion criteria you will use to select studies.
• You plan for managing a tracking search  results
• How you will extract data, assess risk of bias, synthesize data, and grade the evidence.
• PRISMA-P 2015 checklist: recommended items to address in a systematic review protocol PRISMA-P was published in 2015 as a PRISMA extension, aiming to facilitate the development and reporting of systematic review protocols.

Protocol registries were developed in response to an increasing number of systematic reviews being written, increasing the likelihood of duplication of reviews. Protocols are registered during the initial stages of the review. Registering your protocol will:

• Increase transparency.
• Reduce the risk of duplicate reviews.
• Potentially increase visibility to researchers or editors.
• Establish credibility and accountability.
• PROSPERO The largest, independent, International prospective register of systematic reviews protocols. PROSPERO includes protocol details for systematic reviews relevant to health and social care, welfare, public health, education, crime, justice, and international development, where there is a health related outcome.
• PROSPERO Review Registration Guidance Notes

You can also register your protocol with the following organizations, all of which provide instruction on preparing your protocol for submission:

• The Cochrane Collaboration
• The Campbell Collaboration
• The Joanna Briggs Institute
• Commonly Used Standards
• Additional Standards
• MECIR: Methodological Expectations for Cochrane Intervention Review The Methodological Expectations for Cochrane Intervention Reviews lists the methodological standards by which Cochrane reviews must adhere; standards for planning, conducting the review, and reporting. Even if you're not doing a Cochrane review, these standards provide helpful guidance.
• IOM (Institute of Medicine ) National Academy of Medicine: Standards for Systematic Reviews: Standards for systematic reviews of effectiveness of therapeutic and surgical interventions; includes standards for initiative the review, searching, assessing studies, synthesizing evidence and reporting. Free download to the right of list price.
• Systematic Reviews: CRD's Guidance for Undertaking Reviews in Health Care (Centre for Reviews and Dissemination) Provides practical guidance for undertaking evidence synthesis based on a thorough understanding of systematic review methodology. It presents the core principles of systematic reviewing, and in complementary chapters, highlights issues that are specific to reviews of clinical tests, public health interventions, adverse effects, and economic evaluations.
• JBI Reviewers' Manual (Joanna Brigg's Institute) The JBI Reviewers’ Manual provides authors with a comprehensive guide to conducting JBI systematic reviews.
• Writing a Campbell Systematic Review (Campell Collaboration) Provides guidance for writing a Campbell systematic review.
• " onclick="return springSpace.springTrack.trackLink({link: this,_st_type_id: '2',_st_content_id: '53551759',_st_inc_return: this});">HuGENet™ Handbook of Systematic Reviews A HuGE Review identifies human genetic variants at one or more loci; summarizes what is known about the frequency of these variants in different populations; and describes associations of these variants with disease, as well as their interactions with other known risk factors.
• AHRQ: Methods Guide for Effectiveness and Comparative Effectiveness Reviews (US DHHS Agency for Healthcare Research and Quality) Guidelines on conducting systematic reviews or effectiveness, comparative effectiveness, comparative harms, medical tests. Most of the chapters were published as articles in the Journal of Clinical Epidemiology.
• Reporting Protocols
• PRISMA Checklist
• PRISMA Flow Diagram
• PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) PRISMA is a standard for reporting evidence in systematic reviews and meta-analyses. The PRISMA Statement consists of a 27-item checklist and a four-phase flow diagram. The aim of the PRISMA Statement is to help authors improve the reporting of systematic reviews and meta-analyses.
• PRISMA 27-item checklist
• PRISMA four-phase flow diagram
• Equator Network The Enhancing the QUAlity and Transparency Of health Research (Equator) Network is a collection of reporting guidelines on a variety of studies. This link takes you specifically to the reporting guidelines for Systematic Reviews/Meta-Analyses.

• << Previous: 2. Defining Your Question & Criteria
• Next: 4. Search Terms & Strategies >>
• Last Updated: Oct 26, 2023 1:41 PM
• URL: https://libguides.ucmerced.edu/systematic-reviews

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How to Write a Systematic Review: A Narrative Review

Ali hasanpour dehkordi.

Social Determinants of Health Research Center, Shahrekord University of Medical Sciences, Shahrekord, Iran

Elaheh Mazaheri

1 Health Information Technology Research Center, Student Research Committee, Department of Medical Library and Information Sciences, School of Management and Medical Information Sciences, Isfahan University of Medical Sciences, Isfahan, Iran

Hanan A. Ibrahim

2 Department of International Relations, College of Law, Bayan University, Erbil, Kurdistan, Iraq

Sahar Dalvand

3 MSc in Biostatistics, Health Promotion Research Center, Iran University of Medical Sciences, Tehran, Iran

Reza Ghanei Gheshlagh

4 Spiritual Health Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran

In recent years, published systematic reviews in the world and in Iran have been increasing. These studies are an important resource to answer evidence-based clinical questions and assist health policy-makers and students who want to identify evidence gaps in published research. Systematic review studies, with or without meta-analysis, synthesize all available evidence from studies focused on the same research question. In this study, the steps for a systematic review such as research question design and identification, the search for qualified published studies, the extraction and synthesis of information that pertain to the research question, and interpretation of the results are presented in details. This will be helpful to all interested researchers.

A systematic review, as its name suggests, is a systematic way of collecting, evaluating, integrating, and presenting findings from several studies on a specific question or topic.[ 1 ] A systematic review is a research that, by identifying and combining evidence, is tailored to and answers the research question, based on an assessment of all relevant studies.[ 2 , 3 ] To identify assess and interpret available research, identify effective and ineffective health-care interventions, provide integrated documentation to help decision-making, and identify the gap between studies is one of the most important reasons for conducting systematic review studies.[ 4 ]

In the review studies, the latest scientific information about a particular topic is criticized. In these studies, the terms of review, systematic review, and meta-analysis are used instead. A systematic review is done in one of two methods, quantitative (meta-analysis) and qualitative. In a meta-analysis, the results of two or more studies for the evaluation of say health interventions are combined to measure the effect of treatment, while in the qualitative method, the findings of other studies are combined without using statistical methods.[ 5 ]

Since 1999, various guidelines, including the QUORUM, the MOOSE, the STROBE, the CONSORT, and the QUADAS, have been introduced for reporting meta-analyses. But recently the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement has gained widespread popularity.[ 6 , 7 , 8 , 9 ] The systematic review process based on the PRISMA statement includes four steps of how to formulate research questions, define the eligibility criteria, identify all relevant studies, extract and synthesize data, and deduce and present results (answers to research questions).[ 2 ]

Systematic Review Protocol

Systematic reviews start with a protocol. The protocol is a researcher road map that outlines the goals, methodology, and outcomes of the research. Many journals advise writers to use the PRISMA statement to write the protocol.[ 10 ] The PRISMA checklist includes 27 items related to the content of a systematic review and meta-analysis and includes abstracts, methods, results, discussions, and financial resources.[ 11 ] PRISMA helps writers improve their systematic review and meta-analysis report. Reviewers and editors of medical journals acknowledge that while PRISMA may not be used as a tool to assess the methodological quality, it does help them to publish a better study article [ Figure 1 ].[ 12 ]

Screening process and articles selection according to the PRISMA guidelines

The main step in designing the protocol is to define the main objectives of the study and provide some background information. Before starting a systematic review, it is important to assess that your study is not a duplicate; therefore, in search of published research, it is necessary to review PREOSPERO and the Cochrane Database of Systematic. Sometimes it is better to search, in four databases, related systematic reviews that have already been published (PubMed, Web of Sciences, Scopus, Cochrane), published systematic review protocols (PubMed, Web of Sciences, Scopus, Cochrane), systematic review protocols that have already been registered but have not been published (PROSPERO, Cochrane), and finally related published articles (PubMed, Web of Sciences, Scopus, Cochrane). The goal is to reduce duplicate research and keep up-to-date systematic reviews.[ 13 ]

Research questions

Writing a research question is the first step in systematic review that summarizes the main goal of the study.[ 14 ] The research question determines which types of studies should be included in the analysis (quantitative, qualitative, methodic mix, review overviews, or other studies). Sometimes a research question may be broken down into several more detailed questions.[ 15 ] The vague questions (such as: is walking helpful?) makes the researcher fail to be well focused on the collected studies or analyze them appropriately.[ 16 ] On the other hand, if the research question is rigid and restrictive (e.g., walking for 43 min and 3 times a week is better than walking for 38 min and 4 times a week?), there may not be enough studies in this area to answer this question and hence the generalizability of the findings to other populations will be reduced.[ 16 , 17 ] A good question in systematic review should include components that are PICOS style which include population (P), intervention (I), comparison (C), outcome (O), and setting (S).[ 18 ] Regarding the purpose of the study, control in clinical trials or pre-poststudies can replace C.[ 19 ]

Search and identify eligible texts

After clarifying the research question and before searching the databases, it is necessary to specify searching methods, articles screening, studies eligibility check, check of the references in eligible studies, data extraction, and data analysis. This helps researchers ensure that potential biases in the selection of potential studies are minimized.[ 14 , 17 ] It should also look at details such as which published and unpublished literature have been searched, how they were searched, by which mechanism they were searched, and what are the inclusion and exclusion criteria.[ 4 ] First, all studies are searched and collected according to predefined keywords; then the title, abstract, and the entire text are screened for relevance by the authors.[ 13 ] By screening articles based on their titles, researchers can quickly decide on whether to retain or remove an article. If more information is needed, the abstracts of the articles will also be reviewed. In the next step, the full text of the articles will be reviewed to identify the relevant articles, and the reason for the removal of excluded articles is reported.[ 20 ] Finally, it is recommended that the process of searching, selecting, and screening articles be reported as a flowchart.[ 21 ] By increasing research, finding up-to-date and relevant information has become more difficult.[ 22 ]

Currently, there is no specific guideline as to which databases should be searched, which database is the best, and how many should be searched; but overall, it is advisable to search broadly. Because no database covers all health topics, it is recommended to use several databases to search.[ 23 ] According to the A MeaSurement Tool to Assess Systematic Reviews scale (AMSTAR) at least two databases should be searched in systematic and meta-analysis, although more comprehensive and accurate results can be obtained by increasing the number of searched databases.[ 24 ] The type of database to be searched depends on the systematic review question. For example, in a clinical trial study, it is recommended that Cochrane, multi-regional clinical trial (mRCTs), and International Clinical Trials Registry Platform be searched.[ 25 ]

For example, MEDLINE, a product of the National Library of Medicine in the United States of America, focuses on peer-reviewed articles in biomedical and health issues, while Embase covers the broad field of pharmacology and summaries of conferences. CINAHL is a great resource for nursing and health research and PsycINFO is a great database for psychology, psychiatry, counseling, addiction, and behavioral problems. Also, national and regional databases can be used to search related articles.[ 26 , 27 ] In addition, the search for conferences and gray literature helps to resolve the file-drawn problem (negative studies that may not be published yet).[ 26 ] If a systematic review is carried out on articles in a particular country or region, the databases in that region or country should also be investigated. For example, Iranian researchers can use national databases such as Scientific Information Database and MagIran. Comprehensive search to identify the maximum number of existing studies leads to a minimization of the selection bias. In the search process, the available databases should be used as much as possible, since many databases are overlapping.[ 17 ] Searching 12 databases (PubMed, Scopus, Web of Science, EMBASE, GHL, VHL, Cochrane, Google Scholar, Clinical trials.gov, mRCTs, POPLINE, and SIGLE) covers all articles published in the field of medicine and health.[ 25 ] Some have suggested that references management software be used to search for more easy identification and removal of duplicate articles from several different databases.[ 20 ] At least one search strategy is presented in the article.[ 21 ]

Quality assessment

The methodological quality assessment of articles is a key step in systematic review that helps identify systemic errors (bias) in results and interpretations. In systematic review studies, unlike other review studies, qualitative assessment or risk of bias is required. There are currently several tools available to review the quality of the articles. The overall score of these tools may not provide sufficient information on the strengths and weaknesses of the studies.[ 28 ] At least two reviewers should independently evaluate the quality of the articles, and if there is any objection, the third author should be asked to examine the article or the two researchers agree on the discussion. Some believe that the study of the quality of studies should be done by removing the name of the journal, title, authors, and institutions in a Blinded fashion.[ 29 ]

There are several ways for quality assessment, such as Sack's quality assessment (1988),[ 30 ] overview quality assessment questionnaire (1991),[ 31 ] CASP (Critical Appraisal Skills Program),[ 32 ] and AMSTAR (2007),[ 33 ] Besides, CASP,[ 34 ] the National Institute for Health and Care Excellence,[ 35 ] and the Joanna Briggs Institute System for the Unified Management, Assessment and Review of Information checklists.[ 30 , 36 ] However, it is worth mentioning that there is no single tool for assessing the quality of all types of reviews, but each is more applicable to some types of reviews. Often, the STROBE tool is used to check the quality of articles. It reviews the title and abstract (item 1), introduction (items 2 and 3), implementation method (items 4–12), findings (items 13–17), discussion (Items 18–21), and funding (item 22). Eighteen items are used to review all articles, but four items (6, 12, 14, and 15) apply in certain situations.[ 9 ] The quality of interventional articles is often evaluated by the JADAD tool, which consists of three sections of randomization (2 scores), blinding (2 scores), and patient count (1 scores).[ 29 ]

Data extraction

At this stage, the researchers extract the necessary information in the selected articles. Elamin believes that reviewing the titles and abstracts and data extraction is a key step in the review process, which is often carried out by two of the research team independently, and ultimately, the results are compared.[ 37 ] This step aimed to prevent selection bias and it is recommended that the chance of agreement between the two researchers (Kappa coefficient) be reported at the end.[ 26 ] Although data collection forms may differ in systematic reviews, they all have information such as first author, year of publication, sample size, target community, region, and outcome. The purpose of data synthesis is to collect the findings of eligible studies, evaluate the strengths of the findings of the studies, and summarize the results. In data synthesis, we can use different analysis frameworks such as meta-ethnography, meta-analysis, or thematic synthesis.[ 38 ] Finally, after quality assessment, data analysis is conducted. The first step in this section is to provide a descriptive evaluation of each study and present the findings in a tabular form. Reviewing this table can determine how to combine and analyze various studies.[ 28 ] The data synthesis approach depends on the nature of the research question and the nature of the initial research studies.[ 39 ] After reviewing the bias and the abstract of the data, it is decided that the synthesis is carried out quantitatively or qualitatively. In case of conceptual heterogeneity (systematic differences in the study design, population, and interventions), the generalizability of the findings will be reduced and the study will not be meta-analysis. The meta-analysis study allows the estimation of the effect size, which is reported as the odds ratio, relative risk, hazard ratio, prevalence, correlation, sensitivity, specificity, and incidence with a confidence interval.[ 26 ]

Estimation of the effect size in systematic review and meta-analysis studies varies according to the type of studies entered into the analysis. Unlike the mean, prevalence, or incidence index, in odds ratio, relative risk, and hazard ratio, it is necessary to combine logarithm and logarithmic standard error of these statistics [ Table 1 ].

Effect size in systematic review and meta-analysis

OR=Odds ratio; RR=Relative risk; RCT= Randomized controlled trial; PPV: positive predictive value; NPV: negative predictive value; PLR: positive likelihood ratio; NLR: negative likelihood ratio; DOR: diagnostic odds ratio

Interpreting and presenting results (answers to research questions)

A systematic review ends with the interpretation of results. At this stage, the results of the study are summarized and the conclusions are presented to improve clinical and therapeutic decision-making. A systematic review with or without meta-analysis provides the best evidence available in the hierarchy of evidence-based practice.[ 14 ] Using meta-analysis can provide explicit conclusions. Conceptually, meta-analysis is used to combine the results of two or more studies that are similar to the specific intervention and the similar outcomes. In meta-analysis, instead of the simple average of the results of various studies, the weighted average of studies is reported, meaning studies with larger sample sizes account for more weight. To combine the results of various studies, we can use two models of fixed and random effects. In the fixed-effect model, it is assumed that the parameters studied are constant in all studies, and in the random-effect model, the measured parameter is assumed to be distributed between the studies and each study has measured some of it. This model offers a more conservative estimate.[ 40 ]

Three types of homogeneity tests can be used: (1) forest plot, (2) Cochrane's Q test (Chi-squared), and (3) Higgins I 2 statistics. In the forest plot, more overlap between confidence intervals indicates more homogeneity. In the Q statistic, when the P value is less than 0.1, it indicates heterogeneity exists and a random-effect model should be used.[ 41 ] Various tests such as the I 2 index are used to determine heterogeneity, values between 0 and 100; the values below 25%, between 25% and 50%, and above 75% indicate low, moderate, and high levels of heterogeneity, respectively.[ 26 , 42 ] The results of the meta-analyzing study are presented graphically using the forest plot, which shows the statistical weight of each study with a 95% confidence interval and a standard error of the mean.[ 40 ]

The importance of meta-analyses and systematic reviews in providing evidence useful in making clinical and policy decisions is ever-increasing. Nevertheless, they are prone to publication bias that occurs when positive or significant results are preferred for publication.[ 43 ] Song maintains that studies reporting a certain direction of results or powerful correlations may be more likely to be published than the studies which do not.[ 44 ] In addition, when searching for meta-analyses, gray literature (e.g., dissertations, conference abstracts, or book chapters) and unpublished studies may be missed. Moreover, meta-analyses only based on published studies may exaggerate the estimates of effect sizes; as a result, patients may be exposed to harmful or ineffective treatment methods.[ 44 , 45 ] However, there are some tests that can help in detecting negative expected results that are not included in a review due to publication bias.[ 46 ] In addition, publication bias can be reduced through searching for data that are not published.

Systematic reviews and meta-analyses have certain advantages; some of the most important ones are as follows: examining differences in the findings of different studies, summarizing results from various studies, increased accuracy of estimating effects, increased statistical power, overcoming problems related to small sample sizes, resolving controversies from disagreeing studies, increased generalizability of results, determining the possible need for new studies, overcoming the limitations of narrative reviews, and making new hypotheses for further research.[ 47 , 48 ]

Despite the importance of systematic reviews, the author may face numerous problems in searching, screening, and synthesizing data during this process. A systematic review requires extensive access to databases and journals that can be costly for nonacademic researchers.[ 13 ] Also, in reviewing the inclusion and exclusion criteria, the inevitable mindsets of browsers may be involved and the criteria are interpreted differently from each other.[ 49 ] Lee refers to some disadvantages of these studies, the most significant ones are as follows: a research field cannot be summarized by one number, publication bias, heterogeneity, combining unrelated things, being vulnerable to subjectivity, failing to account for all confounders, comparing variables that are not comparable, just focusing on main effects, and possible inconsistency with results of randomized trials.[ 47 ] Different types of programs are available to perform meta-analysis. Some of the most commonly used statistical programs are general statistical packages, including SAS, SPSS, R, and Stata. Using flexible commands in these programs, meta-analyses can be easily run and the results can be readily plotted out. However, these statistical programs are often expensive. An alternative to using statistical packages is to use programs designed for meta-analysis, including Metawin, RevMan, and Comprehensive Meta-analysis. However, these programs may have limitations, including that they can accept few data formats and do not provide much opportunity to set the graphical display of findings. Another alternative is to use Microsoft Excel. Although it is not a free software, it is usually found in many computers.[ 20 , 50 ]

A systematic review study is a powerful and valuable tool for answering research questions, generating new hypotheses, and identifying areas where there is a lack of tangible knowledge. A systematic review study provides an excellent opportunity for researchers to improve critical assessment and evidence synthesis skills.

Authors' contributions

All authors contributed equally to this work.

Financial support and sponsorship

Conflicts of interest.

There are no conflicts of interest.

Systematic Reviews

• Types of Reviews
• Manuals and Reporting Guidelines
• Develop a research question
• Write and Register a Protocol
• Search the Evidence
• Conduct screening
• Appraise and synthesize
• Report Results
• Additional resources

Examples of protocols!

• Health service use among adults with cerebral palsy: a mixed methods systematic review protocol. (PROSPERO) This PROSPERO protocol was also published in BMJ Open. The full SR was published as https://pubmed.ncbi.nlm.nih.gov/34705276/
• Effectiveness of physiotherapy on migraine. A systematic review protocol (OSF) The full SR was later published as https://pubmed.ncbi.nlm.nih.gov/34936005/
• A systematic review of ivermectin for SARS-CoV-2 (Cochrane)) Example of SR protocol from Cochrane. The finished SR was published here: https://www-cochranelibrary-com.libsrv.wku.edu/cdsr/doi/10.1002/14651858.CD015017.pub3/full
• Evaluating behavioral economic interventions for promoting cancer screening uptake and adherence in targeted populations: a systematic review protocol. (JBI) This protocol was published as a standalone work by JBI (Joanna Briggs), an Australian-based repository. WKU has partial access to JBI content via CINAHL. As of 6/23/22, the completed SR has not yet been published.

ALWAYS write and register a protocol (research plan)  BEFORE proceeding with SR. Protocol includes:

• Title of project
• Rationale (why SR important/needed)
• Inclusion/Exclusion criteria
• Databases and other places you will search for published/unpublished literature, including draft  search strategy.
• Data abstraction/management plan
• Quality/Risk of Bias Assessment (not needed for scoping review)
• Data Synthesis
• Grading of evidence.

Why are protocols important?

How to write a protocol (research plan)

Templates, guidance, and checklists. Think about where you might want to publish your SR -- look at recent examples for guidance.

• Systematic Review Protocol Template Easy-to-use template from Sarah Visintini.
• PRISMA for Systematic Review Protocols (PRISMA-P) Checklist and guidance.
• PROSPERO systematic review protocol template
• OSF Protocol Template This template may be used for all review types.
• Cochrane Protocols If planning a Cochrane review, contact editors before you start. Protocols for Cochrane Reviews are published in the Cochrane Library, and may also be loaded into PROSPERO.
• JBI Scoping Review Template

Places to Register Your Protocol

• PROSPERO (University of York. CRD: Centre for Reviews and Dissemination) Registers systematic reviews, rapid reviews, and umbrella reviews. Probably best-known repository for systematic reviews. Submissions often backlogged.
• OSF (Center for Open Science) Accepts systematic reviews, scoping reviews, and other review types..
• Figshare Accepts many project types including scoping reviews.
• << Previous: Develop a research question
• Next: Search the Evidence >>
• Last Updated: Aug 15, 2023 2:50 PM
• URL: https://libguides.wku.edu/systematicreviews

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Systematic Reviews & Evidence Synthesis Methods

Set protocol.

• Types of Reviews
• Formulate Question
• Find Existing Reviews & Protocols
• Searching Systematically
• Supplementary Searching
• Managing Results
• Glossary of terms
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A protocol outlines your objectives, planned methodology, and eligibility criteria. Developing and publishing a prospective protocol is considered a best practice in conducting a systematic review. Publishing an a prior  protocol (in advance of the work) is a requirement for many publishers and a recommendation of others. Additionally, publishing a complete protocol provides the authors with a set of guidelines to follow while working on the initial review and facilitates reliable reproducibility post-publication.

Elements of a Cochrane protocol

• Research Question  (see next page for more on this)
• Types of studies
• Types of participants
• Types of interventions
• Types of outcome measures
• Databases you will use
• Search terms you will use
• Data collection and analysis

Note: elements may vary by discipline

"The preparation of a protocol is an essential component of the systematic review process; it ensures that a systematic review is carefully planned and that what is planned is explicitly documented before the review starts, thus promoting consistent conduct by the review team, accountability, research integrity, and transparency of the eventual completed review." - Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement

Define eligibility criteria

Eligibility criteria, also known as inclusion/exclusion criteria for a systematic review should be established before beginning your review. Eligibility criteria may include the types of studies most relevant for answering your research question. For clinical fields, you may also want to define the population you are looking at and include specifics in your eligibility criteria related to the population data.

Be sure that you have a clear, defensible reason for each criteria you include. While it may be tempting to limit by date or by peer review, this can introduce an element of bias into your methodology. Instead of including only peer reviewed articles, consider empirical studies as an eligibility criteria.

If you want to exclude older papers that may not be as relevant to your research question, think about why a particular date may be relevant. For example, was a technique, technology, or theory essential to your research question developed in a certain year? Then you have defensible grounds for excluding papers written before that year.

Librarian tip:  Review existing systematic reviews and protocols on topics similar to yours to see what types of eligibility criteria other authors are using. This can guide you in developing your own.

• Examples of eligibility criteria for your protocol (PDF) This PDF provides an idea of what your eligibility criteria might look like for your protocol.

Describe Data Collection and Analysis plan

As part of your protocol, you will want to think through the types of data and outcomes that you will be looking for in the studies. Sometimes a systematic review is part of a meta-analysis, but even if you don't plan to conduct that level of data analysis, you should clearly state in your protocol what data you are looking for in the studies. This may be qualitative, quantitative, or mixed data.

For an example of this, view the Data Collection and Analysis section of this protocol registered in the Cochrane Library.

Aye, S.Z., Ni, H., Sein, H.H., Mon, S.T., Zheng, Q., & Wong, Y.K.Y. (2019) D‐cycloserine for autism spectrum disorder . Cochrane Database of Systematic Reviews.  Issue 10. Art. No.: CD013457. DOI: 10.1002/14651858.CD013457.

Determine team and roles

As part of your Protocol, you will want to consider if you have an appropriately sized team of researchers for conducting a Systematic Review. Disciplines vary on team size expectations, however there are some general best practices that you may want to consider.

• It will also be helpful at this stage to outline how you will resolve disagreements about which studies meet eligibility criteria
• 2+ team members involved in data analysis
• Librarian involvement, including peer review of search strategies using  PRESS  guidelines, see  Librarian Support  page for more information

Establishing team member roles in advance is extremely beneficial for smoothly conducting and documenting the Systematic Review process.

Recommended Tools

Before starting on your review, it is helpful to read existing reviews to help understand the project management implications of your review. 

Creating a Systematic Review Protocol (3:16 minutes)

Register Your Protocol

Registering your protocol claims your review topic and makes public your plans. Sometimes the registration site is obvious but there are some of the options:

• Campbell For social science reviews. Draft protocols are peer reviewed.
• Cochrane For health care reviews. Submission of a draft protocol follows acceptance of a topic. A draft protocol undergoes peer review.
• Collaboration for Environmental Evidence For reviews on the impact of human activity. Protocols are submitted to a peer review process.
• Open Science Framework For science reviews. Protocols are not peer reviewed but are registered and available for access.
• Prospero For reviews with a health-related outcome. Protocols are not peer-reviewed but must be registered before "data extraction" has started.
• Last Updated: Oct 30, 2023 6:24 AM
• URL: https://guides.lib.utexas.edu/systematicreviews

Systematic Reviews and Meta-Analyses: Protocol

• Get Started
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A protocol developed before starting the review is a defining feature of the systematic review and/or meta-analysis.

Reporting Guideline for Protocol Development

PRISMA-P  is a reporting guideline for developing the protocol . It should be used in conjunction with a   systematic review and/or meta-analysis reporting guideline (e.g., PRISMA). However, other systematic review and/or meta-analysis reporting guidelines can also support the development of your protocol (e.g., PRISMA, NIRO, ROSES).

It is important to know where you are headed, so a good first step is becoming familiar with each stage (e.g., tab in this guide, section in a handbook) of the systematic review before drafting the protocol.

About Protocols

• Why Protocol?
• Development

Why start with a protocol?

Defining the protocol at the start of your review is one of the mechanisms used to reduce risk of bias . Think of the protocol as a map to your review journey - outlining the path you'll take before you begin will reduce the need for ad hoc decision-making mid-review. Ad hoc decision making is an invitation for bias!

 Joanna Briggs Institute (JBI) Manual for Evidence Synthesis

An essential step in the early development of a systematic review is the development of a review protocol. A protocol pre-defines the objectives and methods of the systematic review which allows transparency of the process which in turns allows the reader to see how the findings and recommendations were arrived at . It must be done prior to conducting the systematic review as it is important in restricting the presence of reporting bias. The protocol is a completely separate document to the systematic review report.

PRISMA Authors

Without review protocols, how can we be assured that decisions made during the research process aren’t arbitrary , or that the decision to include/exclude studies/data in a review aren’t made in light of knowledge about individual study findings?...Given their costly time and resource requirements , we simply cannot afford wasted efforts when it comes to systematic reviews. 

In the context of systematic reviews and meta-analyses, a protocol is a document that presents an explicit scientific “road map” of a planned, uninitiated systematic review. The protocol details the rational and planned methodological and analytical approach of the review.

Develop the protocol before conducting review

According to PRISMA-P:

Arguably one of the most important functions of systematic review protocols is their role as a documentation of planned review methods , outcomes , and analyses that can be compared with completed reviews to detect whether unintended and undocumented changes were made. Bias related to selective reporting of outcomes (that is, when reporting is related to the statistical significance or direction of effect estimate) is a problem in clinical research ...When reviewers selectively choose which information to include in a report based on the direction and significance of findings, they risk biasing the evidence base on which healthcare decisions and policies are made.

Although this excerpt mentions clinical research, research in any field is susceptible to  selective reporting bias . The development of a protocol before beginning your review will help to hold your team accountable to what you set out to do. It is one of several measures taken to reduce the risk of biasing results from a systematic review and/or meta-analysis.

What goes in a protocol?

The PRISMA-P elaboration and explanation document details the items that should be addressed in a systematic review and/or meta-analysis protocol. These items are addressed  throughout this library guide , as applicable.

Pilot the protocol

There are several approaches to piloting your review protocol. Regardless of how it's done, it is a vital part of the process. Piloting helps a team identify and address issues early on so that these issues don't cause a more serious problem (like having to redo a whole stage of the review) down the road.

Basic approaches

Your team may choose to pilot all of the stages of the review, from search to synthesis, before finalizing and registering the protocol. This process is described in Long, 2014 "Routine piloting in systematic reviews--a modified approach? "

At a minimum, your team should pilot each stage as you go through the review itself. For example, during the  eligibility screening  stage, start by having the two reviewers review only 5-10% of the unique references from your search. Calculate the interrater reliability . A low score indicates a lack of consistency between reviewers, which may mean the eligibility criteria needs clarification or to be refined. The pilot concludes when reviewers are screening articles with relative consistency and confidence in applying eligibility criteria.

Why register?

One of the first steps in your systematic review and/or meta-analysis journey was to identify in-progress reviews . Registering your protocol allows others to know that your review is underway . Registering will also help to keep your team accountable by having a public record of what you aim to accomplish and how. 

Some journals use a pre-registration peer-review model, meaning you can receive feedback  before  starting the review by first registering your protocol. In some cases, if a journal publishes your protocol and your team does not deviate beyond reason, the journal will also publish the final systematic review and/or meta-analysis.

Where to register?

Submit for approval

• Campbell Systematic Reviews Journal  | Social Sciences, systematic reviews and/or meta-analysis, scoping/mapping reviews; focused on intervention-based research & reviews with stakeholder engagement
• PROCEED | Environmental science, evidence synthesis focused  
• PROSPERO | Health, systematic review and/or meta-analysis, restricted/rapid reviews focused
• Research Registry (Systematic Reviews/Meta-Analyses) |  Health & medicine

No approval required

• Figshare | general-purpose repository
• Open Science Framework (OSF) | general-purpose repository
• VTechWorks | Virginia Tech's Institutional Repository (or another institutional repository), general-purpose

Deviation from the protocol

Deviation from the protocol is expected! But your team should   only deviate from the protocol when it is  necessary .

Deviations mid-review can be avoided by piloting first. If you are already mid-review, but need to deviate from your protocol, be sure to  document all changes  (and justification for those changes) thoroughly, and include a report ( PRISMA-P recommends a chart or table format) of all deviations in the final published protocol .

Protocols that have undergone peer review should also be accompanied by documentation of this process, including links to other relevant documents, as is the case in this example (below).

Methodological Guidance

• Animal, Food
• Social Sciences
• Environmental Sciences

Cochrane Handbook  -  Part 1: About Cochrane Reviews

Chapter II:  Planning a Cochrane Review

• II.1.4 Cochrane protocols
• III.2 Reporting of protocols of new Cochrane Reviews

SYREAF Tutorials

Step 1:  developing a protocol.

Conducting systematic reviews of intervention questions I: Writing the review protocol, formulating the question and searching the literature.  O’Connor AM, Anderson KM, Goodell CK, Sargeant JM. Zoonoses Public Health. 2014 Jun;61 Suppl 1:28-38. doi: 10.1111/zph.12125. PMID: 24905994

Campbell -  MECCIR

MECCIR guidance describes all required and recommend items to be addressed in the Title (T), Protocol (P) , and Review (R). These items are referenced throughout this guide where relevant. 

To submit a Campbell review , authors are required, first, to register a title, then submit a  protocol  before submitting the final manuscript. 

CEE -  Guidelines and Standards for Evidence synthesis in Environmental Management

Section 4.  writing and registering a protocol.

4.1 Purpose of the Protocol

4.2 Developing and writing a protocol

Reporting in Final Manuscript

In the final manuscript |  prisma, registration and protocol , essential items.

• Provide registration information for the review, including register name and registration number , or state that the review was not registered  (Item 24a)
• Indicate where the review protocol can be accessed (such as by providing a citation, DOI, or link) or state that a protocol was not prepared  (Item 24b)
• Report details of any amendments to information provided at registration or in the protocol, noting: (a) the amendment itself, (b) the reason for the amendment, and (c) the stage of the review process at which the amendment was implemented (Item 24c)
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• Step 8: Write the Review

Systematic Reviews: Step 8: Write the Review

Created by health science librarians.

• Step 1: Complete Pre-Review Tasks
• Step 2: Develop a Protocol
• Step 3: Conduct Literature Searches
• Step 4: Manage Citations
• Step 5: Screen Citations
• Step 6: Assess Quality of Included Studies
• Step 7: Extract Data from Included Studies

About Step 8: Write the Review

Write your review, report your review with prisma, review sections, plain language summaries for systematic reviews, writing the review- webinars.

• Writing the Review FAQs

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  Request a systematic or scoping review consultation

Search the FAQs

In Step 8, you will write an article or a paper about your systematic review.  It will likely have five sections: introduction, methods, results, discussion, and conclusion.  You will: 

• Review the reporting standards you will use, such as PRISMA. 
• Gather your completed data tables and PRISMA chart. 
• Write the Introduction to the topic and your study, Methods of your research, Results of your research, and Discussion of your results.
• Write an Abstract describing your study and a Conclusion summarizing your paper. 
• Cite the studies included in your systematic review and any other articles you may have used in your paper. 
• If you wish to publish your work, choose a target journal for your article.

The PRISMA Checklist will help you report the details of your systematic review. Your paper will also include a PRISMA chart that is an image of your research process. 

Click an item below to see how it applies to Step 8: Write the Review.

Reporting your review with PRISMA

To write your review, you will need the data from your PRISMA flow diagram .  Review the PRISMA checklist to see which items you should report in your methods section.

Managing your review with Covidence

When you screen in Covidence, it will record the numbers you need for your PRISMA flow diagram from duplicate removal through inclusion of studies.  You may need to add additional information, such as the number of references from each database, citations you find through grey literature or other searching methods, or the number of studies found in your previous work if you are updating a systematic review.

How a librarian can help with Step 8

A librarian can advise you on the process of organizing and writing up your systematic review, including: 

• Applying the PRISMA reporting templates and the level of detail to include for each element
• How to report a systematic review search strategy and your review methodology in the completed review
• How to use prior published reviews to guide you in organizing your manuscript 

Reporting standards & guidelines

Be sure to reference reporting standards when writing your review. This helps ensure that you communicate essential components of your methods, results, and conclusions. There are a number of tools that can be used to ensure compliance with reporting guidelines. A few review-writing resources are listed below.

• Cochrane Handbook - Chapter 15: Interpreting results and drawing conclusions
• JBI Manual for Evidence Synthesis - Chapter 12.3 The systematic review
• PRISMA 2020 (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) The aim of the PRISMA Statement is to help authors improve the reporting of systematic reviews and meta-analyses.

Tools for writing your review

• RevMan (Cochrane Training)
• Methods Wizard (Systematic Review Accelerator) The Methods Wizard is part of the Systematic Review Accelerator created by Bond University and the Institute for Evidence-Based Healthcare.
• UNC HSL Systematic Review Manuscript Template Systematic review manuscript template(.doc) adapted from the PRISMA 2020 checklist. This document provides authors with template for writing about their systematic review. Each table contains a PRISMA checklist item that should be written about in that section, the matching PRISMA Item number, and a box where authors can indicate if an item has been completed. Once text has been added, delete any remaining instructions and the PRISMA checklist tables from the end of each section.
• The PRISMA 2020 statement: an updated guideline for reporting systematic reviews The PRISMA 2020 statement replaces the 2009 statement and includes new reporting guidance that reflects advances in methods to identify, select, appraise, and synthesise studies.
• PRISMA 2020 explanation and elaboration: updated guidance and exemplars for reporting systematic reviews This document is intended to enhance the use, understanding and dissemination of the PRISMA 2020 Statement. Through examples and explanations, the meaning and rationale for each checklist item are presented.

The PRISMA checklist

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) is a 27-item checklist used to improve transparency in systematic reviews. These items cover all aspects of the manuscript, including title, abstract, introduction, methods, results, discussion, and funding. The PRISMA checklist can be downloaded in PDF or Word files.

• PRISMA 2020 Checklists Download the 2020 PRISMA Checklists in Word or PDF formats or download the expanded checklist (PDF).

The PRISMA flow diagram

The PRISMA Flow Diagram visually depicts the flow of studies through each phase of the review process. The PRISMA Flow Diagram can be downloaded in Word files.

• PRISMA 2020 Flow Diagrams The flow diagram depicts the flow of information through the different phases of a systematic review. It maps out the number of records identified, included and excluded, and the reasons for exclusions. Different templates are available depending on the type of review (new or updated) and sources used to identify studies.

Documenting grey literature and/or hand searches

If you have also searched additional sources, such as professional organization websites, cited or citing references, etc., document your grey literature search using the flow diagram template version 1 PRISMA 2020 flow diagram for new systematic reviews which included searches of databases, registers and other sources or the version 2 PRISMA 2020 flow diagram for updated systematic reviews which included searches of databases, registers and other sources . 

Complete the boxes documenting your database searches,  Identification of studies via databases and registers, according to the PRISMA flow diagram instructions.  Complete the boxes documenting your grey literature and/or hand searches on the right side of the template, Identification of studies via other methods, using the steps below.

Need help completing the PRISMA flow diagram?

There are different PRISMA flow diagram templates for new and updated reviews, as well as different templates for reviews with and without grey literature searches. Be sure you download the correct template to match your review methods, then follow the steps below for each portion of the diagram you have available.

Click to view the step-by-step explanation of the PRISMA flow diagram

Step 1: Preparation Download the flow diagram template version 1 PRISMA 2020 flow diagram for new systematic reviews which included searches of databases and registers only or the version 2 PRISMA 2020 flow diagram for updated systematic reviews which included searches of databases and registers only . 

Click to view the step-by-step explanation of the grey literature & hand searching portion of the PRISMA flow diagram

Step 1: Preparation Download the flow diagram template version 1 PRISMA 2020 flow diagram for new systematic reviews which included searches of databases, registers and other sources or the version 2 PRISMA 2020 flow diagram for updated systematic reviews which included searches of databases, registers and other sources . 

Click to view the step-by-step explanation of review update portion of the PRISMA flow diagram

Step 1: Preparation Download the flow diagram template version 2 PRISMA 2020 flow diagram for updated systematic reviews which included searches of databases and registers only or the version 2 PRISMA 2020 flow diagram for updated systematic reviews which included searches of databases, registers and other sources . 

For more information about updating your systematic review, see the box Updating Your Review? on the Step 3: Conduct Literature Searches page of the guide.

Sections of a Scientific Manuscript

Scientific articles often follow the IMRaD format: Introduction, Methods, Results, and Discussion.  You will also need a title and an abstract to summarize your research.

You can read more about scientific writing through the library guides below.

• Structure of Scholarly Articles & Peer Review • Explains the standard parts of a medical research article • Compares scholarly journals, professional trade journals, and magazines • Explains peer review and how to find peer reviewed articles and journals
• Writing in the Health Sciences (For Students and Instructors)
• Citing & Writing Tools & Guides Includes links to guides for popular citation managers such as EndNote, Sciwheel, Zotero; copyright basics; APA & AMA Style guides; Plagiarism & Citing Sources; Citing & Writing: How to Write Scientific Papers

Sections of a Systematic Review Manuscript

Systematic reviews follow the same structure as original research articles, but you will need to report on your search instead of on details like the participants or sampling. Sections of your manuscript are shown as bold headings in the PRISMA checklist.

Refer to the PRISMA checklist for more information.

Consider including a Plain Language Summary (PLS) when you publish your systematic review. Like an abstract, a PLS gives an overview of your study, but is specifically written and formatted to be easy for non-experts to understand. 

Tips for writing a PLS:

• Use clear headings e.g. "why did we do this study?"; "what did we do?"; "what did we find?"
• Use active voice e.g. "we searched for articles in 5 databases instead of "5 databases were searched"
• Consider need-to-know vs. nice-to-know: what is most important for readers to understand about your study? Be sure to provide the most important points without misrepresenting your study or misleading the reader. 
• Keep it short: Many journals recommend keeping your plain language summary less than 250 words. 
• Check journal guidelines: Your journal may have specific guidelines about the format of your plain language summary and when you can publish it. Look at journal guidelines before submitting your article. 

Learn more about Plain Language Summaries: 

• Rosenberg, A., Baróniková, S., & Feighery, L. (2021). Open Pharma recommendations for plain language summaries of peer-reviewed medical journal publications. Current Medical Research and Opinion, 37(11), 2015–2016.  https://doi.org/10.1080/03007995.2021.1971185
• Lobban, D., Gardner, J., & Matheis, R. (2021). Plain language summaries of publications of company-sponsored medical research: what key questions do we need to address? Current Medical Research and Opinion, 1–12. https://doi.org/10.1080/03007995.2021.1997221
• Cochrane Community. (2022, March 21). Updated template and guidance for writing Plain Language Summaries in Cochrane Reviews now available. https://community.cochrane.org/news/updated-template-and-guidance-writing-plain-language-summaries-cochrane-reviews-now-available
• You can also look at our Health Literacy LibGuide:  https://guides.lib.unc.edu/healthliteracy 

How to Approach Writing a Background Section

What Makes a Good Discussion Section

Writing Up Risk of Bias

Developing Your Implications for Research Section

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Systematic reviews

• Introduction
• How do systematic reviews differ from other types of reviews?
• Cochrane Interactive Learning
• Reporting standards
• Step one: Forming a research question
• Step two: Creating a protocol
• Searching effectively
• Understanding search strategies
• Finding grey literature
• Software and tools
• Critical appraisal This link opens in a new window
• Further support

What is a protocol?

A systematic review protocol contains a comprehensive description of your systematic review, including the rationale, hypothesis and the methods you intend to follow.

The Cochrane Collaboration have produced an online learning tool on writing a protocol which you can use to help structure and design your protocol.

You have access to this Cochane learning package through the university. If you don't currently have a Cochrane Interactive Learning account, please create one using the link below:

• Cochrane Interactive Learning - Registration and annual re-registration only This link opens in a new window Personal account required. Use this link to register for an account. For help registering or re-registering access guidance here.

Guidance on writing a protocol

The following resources can be used to help prepare a systematic review protocol

• PRISMA extension for Protocols
• Cochrane Handbook - Chapter 4
• Institute of Medicine – Standards for systematic reviews (section 2.6)

Registering your protocol

Registries can also be used to compare research methodologies across systematic reviews and for peer-review. 

• << Previous: Step one: Forming a research question
• Next: Step three: Choosing and searching databases >>
• Last Updated: Nov 2, 2023 11:52 AM
• URL: https://libguides.exeter.ac.uk/systematicreviews

Doing a systematic review

Creating a protocol, pico framework for structuring your research, alternative frameworks.

• Step 2: choosing where to search
• Step 3: developing a search strategy
• Step 4: running & recording your search
• Step 5: managing your search results
• Step 6: screening & evaluating
• Step 7: synthesis and writing it up (including PRISMA flow diagrams)

Finding reviews in progress and examples

Use the PROSPERO database to find examples of protocols and details of reviews in progress. If you are planning to publish your review check PROSPERO to make sure someone isn't already investigating that area. It is also a good idea to register your own review here once you've established its uniqueness.

• PROSPERO This international database covers prospectively registered systematic reviews in health and social care, welfare, public health, education, crime, justice, and international development, where there is a health related outcome.

Software for managing your review

• RevMan Review Manager (RevMan) is Cochrane's software for preparing and maintaining Cochrane reviews, although it can be used for non-Cochrane reviews too. If you are doing a professional systematic review leading to publication you may wish to consider using it to help manage the process. RevMan facilitates preparation of protocols and full reviews, including text, characteristics of studies, comparison tables, and study data. It can perform meta-analysis of the data entered, and present results graphically.

• research question and aims
• criteria for inclusion and exclusion
• search strategy
• selecting studies for inclusion
• quality assessment
• data extraction & analysis
• synthesis of results
• dissemination
• time frame.

You may wish to do some scoping searches of relevant databases to find out how much has been written, and what limits you should apply.

• Systematic review protocol template Use this Word document to help you plan your review and develop your protocol
• Systematic review protocol example An example of using the protocol template to plan a systematic review.
• The review protocol Produced by the Centre for Reviews and Dissemination this detailed guidance covers elements to consider when creating a review protocol.
• Watch our video introductions to doing a systematic review Watch video 2 in our series of videos on doing a systematic review for brief guidance on creating your protocol.

There are several different frameworks you can use to help structure your research and ensure you have clear parameters for your search. The most commonly used one used for health-related reviews is the PICO framework:

• Population This could be the general population, or a specific group defined by: age (e.g. infants, children, adolescents, elderly); socioeconomic status (e.g. low-income, homeless); risk status; location (rural or urban)
• Intervention Refers to the therapy, test, strategy to be investigated (e.g. drug, behavioural change, environmental factors, counselling)
• Comparator A measure you will use to compare results against (e.g. no treatment, alternative treatment/exposure, standard/routine interventions)
• Outcome What outcome is significant to your population or issue? This may be different from the outcome measures used in the studies.

PICO example

This example is extracted from: PROSPERO 2018 CRD42018100888 .

Further information

• Developing an efficient search strategy using PICO A tool created by Health Evidence which can be used to: develop a clear, answerable question that can be used to generate a search strategy; identify key search terms to facilitate a more efficient search; and to document search strategies/terms for future search updates, either in the same or similar topics.

Another framework may be more suitable depending on your review topic. Here are some other options:

• PECO – Population | Environment | Comparison | Outcome Very similar to PICO but looking at the effect of exposure to something e.g. smoky atmosphere
• SPICE - Setting | Population | Intervention | Comparison | Evaluation Another variant of PICO but this time including the setting (where? in what context?)
• CIMO - Context | Intervention | Mechanisms | Outcome A variant of PICO suitable for management and organisation studies
• ECLIPSE - Expectation | Client group | Location | Impact | Professionals | SErvice Recommended for health policy/management searches
• SPIDER – Sample | Phenomenon of Interest | Design | Evaluation | Research Type Developed to create effective search strategies of qualitative and mixed-methods research - more specific than PICO/PECO
• Developing a research question This guide from the University of Maryland includes a comprehensive list of other frameworks.
• How CLIP became ECLIPSE: a mnemonic to assist in searching for health policy/management information Article about the development of the ECLIPSE framework.
• Beyond PICO: the SPIDER tool for qualitative evidence synthesis. A comparison of the PICO and SPIDER frameworks for creating search strategies.
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Systematic reviews.

• What is a Systematic Review?
• Getting started
• Planning your search
• Writing a protocol
• Transferring your search
• Managing your references
• Further help and support

What is a protocol? 

Protocol guidance can be found in PRISMA P statement   (medicine and health-related disciplines) or from ROSES (environmental science related disciplines).

Take a look at the following for further information:

• PRISMA checklist
• PRISMA flow diagram
• ROSES for systematic map protocol
• ROSES for systematic review protocol
• ROSES flow diagram

Your protocol needs to include the following and its aim is to keep your SR on track and focused.

• Rationale / conceptual discussion of problem (background info)
• The review question (s) and objective (s)
• Search strategy
• Study selection criteria
• Study quality assessment
• Data extraction procedure
• Data synthesis procedure
• Project timetable

Where do I register it?

• PROSPERO  -  International Prospective Register of Systematic Reviews. Registration is free and open to anyone undertaking systematic reviews of the effects of interventions and strategies to prevent, diagnose, treat, and monitor health conditions, for which there is a health related outcome.
• The Cochrane Collaboration: Proposing and registering new reviews  - This page gives the steps on how to register your proposed Cochrane Review with a Cochrane Review Group.
• Center for Open Science  -  Register your protocol or research project, or consider uploading a preprint.

The benefits of a protocol

• Raises awareness of the review
• Promotes a systematic rather than ad hoc approach to the review
• ​Provides a public record of planned methods - reduces risk of bias
• ​Facilitates communication with others and promotes consistency between review team members
• ​​Tracks use and impact of published reviews
• ​Permanent record whether final report published or not

Article: Best Practices in Systematic Reviews: The Importance of Protocols and Registration

If you want to read further, why not check out Planning a Systematic Review: think protocols blog post by BMC on the benefits?

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• Systematic Review | Definition, Example, & Guide

Systematic Review | Definition, Example & Guide

Published on June 15, 2022 by Shaun Turney . Revised on June 22, 2023.

A systematic review is a type of review that uses repeatable methods to find, select, and synthesize all available evidence. It answers a clearly formulated research question and explicitly states the methods used to arrive at the answer.

They answered the question “What is the effectiveness of probiotics in reducing eczema symptoms and improving quality of life in patients with eczema?”

In this context, a probiotic is a health product that contains live microorganisms and is taken by mouth. Eczema is a common skin condition that causes red, itchy skin.

Table of contents

What is a systematic review, systematic review vs. meta-analysis, systematic review vs. literature review, systematic review vs. scoping review, when to conduct a systematic review, pros and cons of systematic reviews, step-by-step example of a systematic review, other interesting articles, frequently asked questions about systematic reviews.

A review is an overview of the research that’s already been completed on a topic.

What makes a systematic review different from other types of reviews is that the research methods are designed to reduce bias . The methods are repeatable, and the approach is formal and systematic:

• Formulate a research question
• Develop a protocol
• Search for all relevant studies
• Apply the selection criteria
• Extract the data
• Synthesize the data
• Write and publish a report

Although multiple sets of guidelines exist, the Cochrane Handbook for Systematic Reviews is among the most widely used. It provides detailed guidelines on how to complete each step of the systematic review process.

Systematic reviews are most commonly used in medical and public health research, but they can also be found in other disciplines.

Systematic reviews typically answer their research question by synthesizing all available evidence and evaluating the quality of the evidence. Synthesizing means bringing together different information to tell a single, cohesive story. The synthesis can be narrative ( qualitative ), quantitative , or both.

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Systematic reviews often quantitatively synthesize the evidence using a meta-analysis . A meta-analysis is a statistical analysis, not a type of review.

A meta-analysis is a technique to synthesize results from multiple studies. It’s a statistical analysis that combines the results of two or more studies, usually to estimate an effect size .

A literature review is a type of review that uses a less systematic and formal approach than a systematic review. Typically, an expert in a topic will qualitatively summarize and evaluate previous work, without using a formal, explicit method.

Although literature reviews are often less time-consuming and can be insightful or helpful, they have a higher risk of bias and are less transparent than systematic reviews.

Similar to a systematic review, a scoping review is a type of review that tries to minimize bias by using transparent and repeatable methods.

However, a scoping review isn’t a type of systematic review. The most important difference is the goal: rather than answering a specific question, a scoping review explores a topic. The researcher tries to identify the main concepts, theories, and evidence, as well as gaps in the current research.

Sometimes scoping reviews are an exploratory preparation step for a systematic review, and sometimes they are a standalone project.

A systematic review is a good choice of review if you want to answer a question about the effectiveness of an intervention , such as a medical treatment.

To conduct a systematic review, you’ll need the following:

• A precise question , usually about the effectiveness of an intervention. The question needs to be about a topic that’s previously been studied by multiple researchers. If there’s no previous research, there’s nothing to review.
• If you’re doing a systematic review on your own (e.g., for a research paper or thesis ), you should take appropriate measures to ensure the validity and reliability of your research.
• Access to databases and journal archives. Often, your educational institution provides you with access.
• Time. A professional systematic review is a time-consuming process: it will take the lead author about six months of full-time work. If you’re a student, you should narrow the scope of your systematic review and stick to a tight schedule.
• Bibliographic, word-processing, spreadsheet, and statistical software . For example, you could use EndNote, Microsoft Word, Excel, and SPSS.

A systematic review has many pros .

• They minimize research bias by considering all available evidence and evaluating each study for bias.
• Their methods are transparent , so they can be scrutinized by others.
• They’re thorough : they summarize all available evidence.
• They can be replicated and updated by others.

Systematic reviews also have a few cons .

• They’re time-consuming .
• They’re narrow in scope : they only answer the precise research question.

The 7 steps for conducting a systematic review are explained with an example.

Step 1: Formulate a research question

Formulating the research question is probably the most important step of a systematic review. A clear research question will:

• Allow you to more effectively communicate your research to other researchers and practitioners
• Guide your decisions as you plan and conduct your systematic review

A good research question for a systematic review has four components, which you can remember with the acronym PICO :

• Population(s) or problem(s)
• Intervention(s)
• Comparison(s)

You can rearrange these four components to write your research question:

• What is the effectiveness of I versus C for O in P ?

Sometimes, you may want to include a fifth component, the type of study design . In this case, the acronym is PICOT .

• Type of study design(s)
• The population of patients with eczema
• The intervention of probiotics
• In comparison to no treatment, placebo , or non-probiotic treatment
• The outcome of changes in participant-, parent-, and doctor-rated symptoms of eczema and quality of life
• Randomized control trials, a type of study design

Their research question was:

• What is the effectiveness of probiotics versus no treatment, a placebo, or a non-probiotic treatment for reducing eczema symptoms and improving quality of life in patients with eczema?

Step 2: Develop a protocol

A protocol is a document that contains your research plan for the systematic review. This is an important step because having a plan allows you to work more efficiently and reduces bias.

Your protocol should include the following components:

• Background information : Provide the context of the research question, including why it’s important.
• Research objective (s) : Rephrase your research question as an objective.
• Selection criteria: State how you’ll decide which studies to include or exclude from your review.
• Search strategy: Discuss your plan for finding studies.
• Analysis: Explain what information you’ll collect from the studies and how you’ll synthesize the data.

If you’re a professional seeking to publish your review, it’s a good idea to bring together an advisory committee . This is a group of about six people who have experience in the topic you’re researching. They can help you make decisions about your protocol.

It’s highly recommended to register your protocol. Registering your protocol means submitting it to a database such as PROSPERO or ClinicalTrials.gov .

Step 3: Search for all relevant studies

Searching for relevant studies is the most time-consuming step of a systematic review.

To reduce bias, it’s important to search for relevant studies very thoroughly. Your strategy will depend on your field and your research question, but sources generally fall into these four categories:

• Databases: Search multiple databases of peer-reviewed literature, such as PubMed or Scopus . Think carefully about how to phrase your search terms and include multiple synonyms of each word. Use Boolean operators if relevant.
• Handsearching: In addition to searching the primary sources using databases, you’ll also need to search manually. One strategy is to scan relevant journals or conference proceedings. Another strategy is to scan the reference lists of relevant studies.
• Gray literature: Gray literature includes documents produced by governments, universities, and other institutions that aren’t published by traditional publishers. Graduate student theses are an important type of gray literature, which you can search using the Networked Digital Library of Theses and Dissertations (NDLTD) . In medicine, clinical trial registries are another important type of gray literature.
• Experts: Contact experts in the field to ask if they have unpublished studies that should be included in your review.

At this stage of your review, you won’t read the articles yet. Simply save any potentially relevant citations using bibliographic software, such as Scribbr’s APA or MLA Generator .

• Databases: EMBASE, PsycINFO, AMED, LILACS, and ISI Web of Science
• Handsearch: Conference proceedings and reference lists of articles
• Gray literature: The Cochrane Library, the metaRegister of Controlled Trials, and the Ongoing Skin Trials Register
• Experts: Authors of unpublished registered trials, pharmaceutical companies, and manufacturers of probiotics

Step 4: Apply the selection criteria

Applying the selection criteria is a three-person job. Two of you will independently read the studies and decide which to include in your review based on the selection criteria you established in your protocol . The third person’s job is to break any ties.

To increase inter-rater reliability , ensure that everyone thoroughly understands the selection criteria before you begin.

If you’re writing a systematic review as a student for an assignment, you might not have a team. In this case, you’ll have to apply the selection criteria on your own; you can mention this as a limitation in your paper’s discussion.

You should apply the selection criteria in two phases:

• Based on the titles and abstracts : Decide whether each article potentially meets the selection criteria based on the information provided in the abstracts.
• Based on the full texts: Download the articles that weren’t excluded during the first phase. If an article isn’t available online or through your library, you may need to contact the authors to ask for a copy. Read the articles and decide which articles meet the selection criteria.

It’s very important to keep a meticulous record of why you included or excluded each article. When the selection process is complete, you can summarize what you did using a PRISMA flow diagram .

Next, Boyle and colleagues found the full texts for each of the remaining studies. Boyle and Tang read through the articles to decide if any more studies needed to be excluded based on the selection criteria.

When Boyle and Tang disagreed about whether a study should be excluded, they discussed it with Varigos until the three researchers came to an agreement.

Step 5: Extract the data

Extracting the data means collecting information from the selected studies in a systematic way. There are two types of information you need to collect from each study:

• Information about the study’s methods and results . The exact information will depend on your research question, but it might include the year, study design , sample size, context, research findings , and conclusions. If any data are missing, you’ll need to contact the study’s authors.
• Your judgment of the quality of the evidence, including risk of bias .

You should collect this information using forms. You can find sample forms in The Registry of Methods and Tools for Evidence-Informed Decision Making and the Grading of Recommendations, Assessment, Development and Evaluations Working Group .

Extracting the data is also a three-person job. Two people should do this step independently, and the third person will resolve any disagreements.

They also collected data about possible sources of bias, such as how the study participants were randomized into the control and treatment groups.

Step 6: Synthesize the data

Synthesizing the data means bringing together the information you collected into a single, cohesive story. There are two main approaches to synthesizing the data:

• Narrative ( qualitative ): Summarize the information in words. You’ll need to discuss the studies and assess their overall quality.
• Quantitative : Use statistical methods to summarize and compare data from different studies. The most common quantitative approach is a meta-analysis , which allows you to combine results from multiple studies into a summary result.

Generally, you should use both approaches together whenever possible. If you don’t have enough data, or the data from different studies aren’t comparable, then you can take just a narrative approach. However, you should justify why a quantitative approach wasn’t possible.

Boyle and colleagues also divided the studies into subgroups, such as studies about babies, children, and adults, and analyzed the effect sizes within each group.

Step 7: Write and publish a report

The purpose of writing a systematic review article is to share the answer to your research question and explain how you arrived at this answer.

Your article should include the following sections:

• Abstract : A summary of the review
• Introduction : Including the rationale and objectives
• Methods : Including the selection criteria, search method, data extraction method, and synthesis method
• Results : Including results of the search and selection process, study characteristics, risk of bias in the studies, and synthesis results
• Discussion : Including interpretation of the results and limitations of the review
• Conclusion : The answer to your research question and implications for practice, policy, or research

To verify that your report includes everything it needs, you can use the PRISMA checklist .

Once your report is written, you can publish it in a systematic review database, such as the Cochrane Database of Systematic Reviews , and/or in a peer-reviewed journal.

If you want to know more about statistics , methodology , or research bias , make sure to check out some of our other articles with explanations and examples.

• Student’s  t -distribution
• Normal distribution
• Null and Alternative Hypotheses
• Chi square tests
• Confidence interval
• Quartiles & Quantiles
• Cluster sampling
• Stratified sampling
• Data cleansing
• Reproducibility vs Replicability
• Peer review
• Prospective cohort study

Research bias

• Implicit bias
• Cognitive bias
• Placebo effect
• Hawthorne effect
• Hindsight bias
• Affect heuristic
• Social desirability bias

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a thesis, dissertation , or research paper , in order to situate your work in relation to existing knowledge.

A literature review is a survey of credible sources on a topic, often used in dissertations , theses, and research papers . Literature reviews give an overview of knowledge on a subject, helping you identify relevant theories and methods, as well as gaps in existing research. Literature reviews are set up similarly to other  academic texts , with an introduction , a main body, and a conclusion .

An  annotated bibliography is a list of  source references that has a short description (called an annotation ) for each of the sources. It is often assigned as part of the research process for a  paper .  

A systematic review is secondary research because it uses existing research. You don’t collect new data yourself.

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The SPIRIT (Standard Protocol Items for Randomized Trials) statement is an evidence-based tool developed through systematic review of a wide range of resources and consensus. It closely mirrors the CONSORT statement and reflects important ethical considerations.

If your protocol is for a systematic review or meta-analysis

We strongly encourage authors and assessors to use the PRISMA-P reporting guideline . The PRISMA-P (Preferred Reporting Items for Systematic review and Meta-Analysis Protocols) checklist contains 17 items considered to be the essential and minimum components of systematic review or meta-analysis protocol. We recommend pre-registration of systematic reviews in registries that are based on the PRISMA-P reporting guideline and on the PROSPERO registration form.

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Systematic Reviews  encourages prospective registration of systematic reviews in PROSPERO  or Open Science Framework and encourages registration of scoping and other types of review in other relevant registration platforms.   Please include the registration number as the last line of your Abstract, under the sub-heading 'Registration'.  If you have submitted your protocol for registration but have not yet received a registration number, please indicate this as 'submitted', along with the date the protocol was submitted for registration.

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Reporting standards

Systematic Reviews requires the submission of a populated PRISMA-P checklist for all study protocols.  The checklist should be provided as an additional file and should be referenced in the text. Submissions received without this element will be returned to the authors as incomplete. The checklist can be found here .

It is understood that for some study protocols certain aspects may not comply fully with the PRISMA-P checklist. The checklist will not be used as a tool for judging the suitability of manuscripts for publication in Systematic Reviews , but is intended as an aid to authors to clearly, completely, and transparently let reviewers and readers know what authors intend to do. Using the PRISMA-P guideline to write the study protocol and completing the PRISMA-P checklist are likely to optimize the quality of reporting and make the peer review process more efficient.

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Please note that your manuscript must include a 'Declarations' section including all of the subheadings (please see below for more information).

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Wyllie AH, Kerr JFR, Currie AR. Cell death: the significance of apoptosis. In: Bourne GH, Danielli JF, Jeon KW, editors. International review of cytology. London: Academic; 1980. p. 251-306.

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Saito Y, Hyuga H. Rate equation approaches to amplification of enantiomeric excess and chiral symmetry breaking. Top Curr Chem. 2007. doi:10.1007/128_2006_108.

Complete book, authored

Blenkinsopp A, Paxton P. Symptoms in the pharmacy: a guide to the management of common illness. 3rd ed. Oxford: Blackwell Science; 1998.

Online document

Doe J. Title of subordinate document. In: The dictionary of substances and their effects. Royal Society of Chemistry. 1999. http://www.rsc.org/dose/title of subordinate document. Accessed 15 Jan 1999.

Online database

Healthwise Knowledgebase. US Pharmacopeia, Rockville. 1998. http://www.healthwise.org. Accessed 21 Sept 1998.

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Doe J. Title of supplementary material. 2000. http://www.privatehomepage.com. Accessed 22 Feb 2000.

University site

Doe, J: Title of preprint. http://www.uni-heidelberg.de/mydata.html (1999). Accessed 25 Dec 1999.

Doe, J: Trivial HTTP, RFC2169. ftp://ftp.isi.edu/in-notes/rfc2169.txt (1999). Accessed 12 Nov 1999.

Organization site

ISSN International Centre: The ISSN register. http://www.issn.org (2006). Accessed 20 Feb 2007.

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Zheng L-Y, Guo X-S, He B, Sun L-J, Peng Y, Dong S-S, et al. Genome data from sweet and grain sorghum (Sorghum bicolor). GigaScience Database. 2011. http://dx.doi.org/10.5524/100012 .

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Systematic Reviews

ISSN: 2046-4053

• Submission enquiries: Access here and click Contact Us
• General enquiries: [email protected]

• Dalhousie University Libraries

Knowledge Syntheses: A How-To Guide

• Planning Your Review
• Before You Begin
• How can the Library Help You?
• Systematic Review
• Scoping Review
• Rapid Review
• Realist Review
• Integrative Review
• Searching & Documenting
• Citation Management
• Screening & Study Selection

Data Extraction

• Appraisal and Analysis
• Writing the Report
• Methods & Training Resources
• Covidence and Other Systematic Management Software

What is a Protocol and Why is it Important?

" systematic reviews should build on a protocol that describes the rationale, hypothesis, and planned methods of the review. detailed, well-described protocols can facilitate the understanding and appraisal of the review methods, as well as the detection of modifications to methods and selective reporting in completed reviews"  (moher, 2015)..

• Systematic Review Protocol Template Fillable Word template
• JBI Scoping Review Protocol Template
• General Evidence Synthesis Protocol Template This document is based on the PRISMA Statement (evidence-based minimum set of items for reporting in systematic reviews and meta-analyses) extensions for systematic review protocols and scoping reviews, and materials developed by The Campbell Collaboration. Created by researchers at Cornell.
• PRISMA-P Reporting guidelines for SR protocols, includes checklist
• Sections to Include in a Protocol Detailed instructions for systematic and scoping review protocols, based on methodological guidance.

Protocol registration or publishing

Systematic review standards require prospectively registering the protocol prior to conducting the review. PROSPERO is one option for health-related systematic reviews. Some review teams may also choose to publish their protocol in a topic-related or synthesis methods journal following peer-review. Cochrane, JBI, and some other synthesis organizations have internal peer-review processes for the review protocol. Registration of the protocol in Open Science Framework (OSF) or another topic or institutional research repository are also options for protocols of other types of reviews, such as scoping reviews, or in other disciplines outside of health.

• PROSPERO - International prospective register of systematic reviews
• Open Science Framework (OSF) Registration of review protocols.

Research Data and Project Management Planning for Reviews

• UCalgary guide to the Portage DMP Assistant for SR Projects This guide has been organized to match the sections in the DMP Assistant template for Systematic Reviews to make it easy to locate the relevant guidance as you fill out each section of the template: 1) Data collection 2) Documentation and metadata 3) Storage and backup 4) Preservation 5) Sharing & reuse Within each of these sections, guidance and examples may be broken down according to stage of the systematic review process including: 1) the planning phase (including protocol creation), 2) location of studies, 3) study selection, 4) data extraction and risk of bias assessment, 5) synthesis (both narrative and/or meta-analysis) and 6) manuscript preparation
• Review Project Management Worksheet example Downloadable Excel sheel created by Dr. K. Alix Hayden and Dr. Zahra Premji for project management of evidence synthesis projects.

Sections to Include in a Protocol

• Systematic Reivew

Identify the report as a protocol for the type of review you're conducting (systematic, scoping, rapid, etc.)

Registration

Where did you register your protocol? OSF? PROSPERO? Other?

• Who is conducting the review? 
• Who is part of your team?
• List all contributors and their roles  
• What did everyone do?
• A helpful tool to determine contributions in an unbiased way is to use the CRediT tool
• Who's the review funder/sponsor?
• What's their role in the review?

Introduction

• What's your reason for producing the review?
• What are you trying to achieve?
• What gap in knowledge is this covering?

Objectives/Review Question

• What specific question is your review addressing?
• Identify the participants, interventions, exposure, issue, comparators & outcomes.

Covidence has written a blog post that can help you begin to think about formulating your review question.

Eligibility Criteria

• What criteria are you using to include and exclude studies from your review?
• E.g. Study design, setting, time frame, date, language, publication status, participants characteristics?  

Source: https://unimelb.libguides.com/c.php?g=492361&p=3368110

Information Sources

• What information sources are you gathering information from?
• E.g. list the databases, study authors, trial registers and grey literature & the dates of coverage you're searching
• If you have a draft for your search, provide it in an Appendix

Study Selection Process

• What will your process for selecting studies entail such as having two independent reviewers?
• (e.g. screening, eligibility & inclusion in meta-anaylsis)

Data Collection and Management

• How will you extract data from reports?
• How will you obtain & confirm data from investigators?   
• How are you going to manage your records & data during your review process?
• List & define all outcomes for which data will be sought, including prioritization of main & additional outcomes, with rationales

Risk of Bias

• How will you assess risk of bias in individual studies (will this be done at outcome or study level or both)? 

Data Synthesis

• What criteria will the study data be quantitatively synthesized? 
• Is there any proposed additional analyses (e.g. sensitivity, subgroup analyses, meta-regression)?
• If not a quantitative synthesis (i.e. qualitative synthesis), describe your method for summarizing data

Example Protocols

• Xiao Z, Baldwin MM, Meinck F, Obsuth I, Murray AL. The impact of childhood psychological maltreatment on mental health outcomes in adulthood: a protocol for a systematic review and meta-analysis Syst Rev. 2021;10(1):224. Published 2021 Aug 12. doi:10.1186/s13643-021-01777-4.
• Milne-Ives M, Swancutt D, Burns L, et al. The Effectiveness and Usability of Online, Group-Based Interventions for People With Severe Obesity: Protocol for a Systematic Review.  JMIR Res Protoc . 2021;10(6):e26619. Published 2021 Jun 30. doi:10.2196/26619. https://www.researchprotocols.org/2021/7/e28083/

Reused with permission from: https://guides.library.utoronto.ca/c.php?g=713309&p=5087816

First author name 1 Second author name 2  Third author name 3 Fourth author name 4 Fifth author name 5 Sixth author name 6 1.  Affiliation 2.  Affiliation 3.  Affiliation 4.  Affiliation 5.  Affiliation 6.  Affiliation

(Maximum - 250 words for Protocols / 500 words for Scoping Reviews)

• State an overarching review objective structured using the key components of the inclusion criteria (approximately one or two sentences).
• e.g. The objective of this scoping review is to understand the extent and type of evidence in relation to (insert field)  

Introduction:

• Briefly describe the rationale for the review considering what is already known on the topic
• (approximately two to three sentences)

Inclusion criteria:

• Summarize the inclusion criteria using the participants, concept, and context (PCC framework) and highlight any relevant exclusions in paragraph format
• Present the information in one to three sentences – NOT under individual subheadings
• List the key information sources searched/to be searched ( those from which the majority of evidence sources were/will be located)
• the date (month/year) the search was conducted (for reviews only)
• any search limits (e.g. language)
• Briefly describe the approach to study selection, data extraction, analysis of the evidence and presentation of the results
• Briefly describe any notable deviations to the methodological approach taken (for reviews only)

Results (For Reviews ONLY):

• The bulk of the abstract should be reserved to convey the main results of the review in relation to the objective/question
• Report the number and type of included evidence as well as any pertinent study characteristics

Conclusions (For Reviews ONLY):

• Provide a conclusion based on a general interpretation of the review findings in line with the review’s objective/s and any limitations of the review
• Briefly convey key implications of the findings for practice and research (if any)

Guidance for authors:

• Describe the rationale for the review considering what is already known on the topic, including information that supports and justifies the selection of inclusion criteria
• Key terms should be defined
• operational definitions narratively explained
• provide some indication that there is evidence available that will meet your inclusion criteria
• A rationale as to why a scoping review was the most appropriate method should also be provided (Approximately 1000 words)
• If there are any existing systematic reviews/scoping reviews, it should be specified how the proposed review will differ
• e.g. The objective of this scoping review is to assess the extent of the literature (insert area/field)

Review question

• Clearly state the review question or questions using the PCC framework (i.e. additional or sub-questions) that the review seeks to answer)
• The review question/s should clearly relate to the objective/s
• List a maximum of five keywords in alphabetical order, separated by a semi-colon and a space
• Ideally these words should be different to those that appear in the title and abstract
• These are for the purposes of meta-data and indexing, and not related to the search strategy

Eligibility criteria

Participants.

• Describe/define participants that will be included
• Specific exclusion criteria based on any participant characteristics should also be stated
• Describe and/or define the concept
• Specific exclusion criteria based on any concept should also be stated
• cultural/sub-cultural factors
• geographic location
• specific racial or gender-based interests
• details about the specific setting
• Specific exclusion criteria based on any context should also be stated.

Types of Sources

Example Text:

The proposed scoping review will be conducted in accordance with the JBI methodology for scoping reviews (insert a citation to the methodology ).

Search strategy

• Studies published in any language (modify as appropriate) will be included
• Studies published since insert date will be included as (justify date range and any language limitations)
• List all information sources (e.g. electronic databases, contact with study authors etc.)

The databases to be searched include (insert databases with platforms as appropriate). Sources of unpublished studies/ gray literature to be searched include (insert text, e.g. trial registers etc).

Study/Source of Evidence selection

Following the search, all identified citations will be collated and uploaded into (insert the name of the bibliographic software or citation management system e.g. EndNote insert version /year (Clarivate Analytics, PA, USA)) and duplicates removed. Following a pilot test, titles and abstracts will then be screened by two or more independent reviewers for assessment against the inclusion criteria for the review. Potentially relevant sources will be retrieved in full and their citation details imported into the JBI System for the Unified Management, Assessment and Review of Information (JBI SUMARI) (JBI, Adelaide, Australia) (insert citation to JBI SUMARI paper ) . The full text of selected citations will be assessed in detail against the inclusion criteria by two or more independent reviewers. Reasons for exclusion of sources of evidence at full text that do not meet the inclusion criteria will be recorded and reported in the scoping review. Any disagreements that arise between the reviewers at each stage of the selection process will be resolved through discussion, or with an additional reviewer/s. The results of the search and the study inclusion process will be reported in full in the final scoping review and presented in a Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for scoping review (PRISMA-ScR) flow diagram (insert citation to PRISMA-ScR statement and include in the reference list).

Data will be extracted from papers included in the scoping review by two or more independent reviewers using a data extraction tool developed by the reviewers. The data extracted will include specific details about the participants, concept, context, study methods and key findings relevant to the review question/s.

• Discuss the planned piloting of the draft extraction form in the protocol, and how this was conducted in the review

A draft extraction form is provided (see Appendix XX). The draft data extraction tool will be modified and revised as necessary during the process of extracting data from each included evidence source. Modifications will be detailed in the scoping review. Any disagreements that arise between the reviewers will be resolved through discussion, or with an additional reviewer/s. If appropriate, authors of papers will be contacted to request missing or additional data, where required.  

• Critical appraisal of individual sources of evidence is generally not required for scoping reviews
• If it will be done, provide a rationale as to why and describe the methods, including tools which will be used

Data Analysis and Presentation

The evidence presented should directly respond to the review objective and question(s), the data is commonly presented graphically or in diagrammatic or tabular form, preparation of the review protocol is the opportunity for authors to pilot and determine how to best present their data or map and provide detailed description for the reader, insert information on data presentation/mapping techniques, if any, a narrative summary will accompany the tabulated and/or charted results and will describe how the results relate to the reviews objective and question/s, acknowledgements.

• Insert the full names and precise contributions of individuals, or institutions, who have not already been listed as co-authors
• Specify if this review is to contribute towards a degree award and for which author (initials)
• The acknowledgement section must be included in the submission title page to facilitate the double-blind peer-review process
• For further guidance, please refer to the JBI Evidence Synthesis manuscript style and preparation guidelines
• Provide details on sources of funding for the review
• Explicitly describe the role of funders in the review process

Conflicts of interest

• Include a statement that describes a potential conflict of interest or any personal, financial, professional, or intellectual bias for any of the authors listed on the manuscript
• If no conflict exists, include the following statement: "There is no conflict of interest in this project."

Appendix I: Search strategy

• For protocols - present a full search strategy for at least one electronic database including planned limits, such that it can be reviewed and repeated
• For systematic reviews, all search strategies should be presented

Appendix II: Data extraction instrument

• Only append the JBI or non-JBI data extraction instrument if the standardized tool has been modified in any way, otherwise simply cite the tool used in the text
• Any modifications made to the instrument should also be described in the text
• Scoping reviews: Lackie, Kelly, Miller, Stephen, Ayn, Caitlyn, et al. Interprofessional collaboration between health professional learners when breaking bad news: a scoping review protocol. JBI Evidence Synthesis. Lippincott Williams & Wilkins: Hagerstown, MD. 2021;19(8):2032-2039. doi:10.11124/JBIES-20-00239. https://sfxhosted.exlibrisgroup.com/dal?sid=Entrez%3APubMed&id=pmid%3A33882558&issn=2689-8381
• Cassidy CE, Beck AJ, Conway A, et al. Using an integrated knowledge translation or other research partnership approach in trainee-led research: a scoping review protocol.  BMJ Open . 2021;11(5):e043756. Published 2021 May 25. doi:10.1136/bmjopen-2020-043756 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8154946/
• JBI Scoping Review Protocol Template The Scoping Review Protocol above is a modified version of the JBI template

Review Management Software

Review management software tools are specifically tailored to the needs of knowledge synthesis teams. In addition to reference management, some of these tools can also help with data extraction, perform meta-analysis, track team progress, and facilitate communication between members. As indicated below, some of these tools are fee-based. You should also bear in mind that not every tool is appropriate for every kind of synthesis or review - be sure to choose the right fit for your project.

• COLANDR Free; requires registration and login. Includes review planning and project management tools as well as collaborative screening.
• Rayyan Rayyan is a Free web application to help systematic review authors and has a mobile app (works offline and then syncs back to servers when online).
• CADIMA Free; Includes training material and offers online training. Developed for syntheses in environmental sciences, but works for reviews across disciplines.
• EPPI-Reviewer 4 Fee-based; offers one-month free trial. Features include data extraction, coding, and meta-analysis.
• Distiller Fee-based; offers special pricing for students (free for 4 months; $15USD/mo after that) and Cochrane Review Groups. Available in two versions (DistillerSR and DistillerCER) with varying features.
• JBI SUMARI tool Free with JBI subscription; requires login. JBI SUMARI supports the entire review process, from drafting your protocol, study selection, critical appraisal, data extraction and synthesis.
• Systematic Review Data Repository (SRDR) Free; requires login. This systematic review repository also acts as a data extraction tool.
• Systematic Review Toolbox Database of tools and software to assist with a variety of evidence synthesis projects

Review Management Software Articles

Article comparing SR management tools by Kohl et al. (2018)

Covidence and Rayyan product review

Article comparing SR management tools by van der Mierden et al. (2019)

Review of JBI SUMARI tool

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• Last Updated: Nov 10, 2023 10:43 AM
• URL: https://dal.ca.libguides.com/systematicreviews