What is a review protocol?
Purpose of a protocol in a review
A protocol serves as a plan which specifies the objectives and methods for the review before the review begins.
A protocol helps to minimise bias in a review by documenting a clearly defined review question, stating the review objectives, and outlining the process for completing the review. Furthermore, it reduces the risk of bias being introduced by reviewers once the review process has commenced.
Once the protocol is completed, it should be registered, or published in a journal, or both. Documenting and registering a protocol leads to transparency as this commits the review team to follow the plan set out by the protocol. It also helps to avoid research wastage by other researchers beginning a review on the same topic.
Developing a detailed, well- constructed and methodically written protocol is key to the production of a high-quality review.
What to include in a protocol?
There are several guidelines available to help with writing protocols, such as the Standards for the REPORTING of PROTOCOLS of new Cochrane Intervention Reviews, and JBI Development of a Scoping Review protocol.
The PRISMA-Protocol (PRISMA-P) checklist is a useful tool to ensure all important elements are reported. PRISMA-P has been developed for systematic review protocols, however relevant elements can be adopted as appropriate for other review types such as scoping reviews. The PRISMA for Scoping Reviews (PRISMA-ScR) supports the reporting of Scoping Reviews. Whilst this is for reporting the full scoping review, protocol and registration are part of the checklist.
Tip
The following modules provide information necessary to complete the sections listed below on what to include in a protocol.
Recomended sections in a protocol
Click on the plus (+) icons below to learn about recommended sections to address in a review protocol.
Administrative details
Administrative details provide information about the review, such its title, abstract and registration details.
It provides information about those involved in creating the review, such as authors, stakeholders, funding, etc.
It can also highlight any conflict of interests or clarify responsibilities to do with any parties involved in creating the review, such as organisations sponsoring a review, or individuals involved in the review (e.g., selecting studies, analysing data or publication).
Introduction (Rationale, objectives and background)
The introduction to the review protocol should include:
- Rationale - a justification for why the review is being carried out and how it will contribute to what is already known.
- Objectives - the specific question/s (including any frameworks used to develop research questions) that the review plans to address.
The introduction should also contain any additional background that helps provide further context for the review.
Eligibility criteria
Eligibility criteria are the selection criteria used when screening to include or exclude a study. These relate back to the research question and form the boundaries of the review.
Information sources
Outlines the specific databases which will be systematically searched for studies to include in the review. Also specifies any other information sources, such as registries, government organisations or web searches, which will be systematically searched.
Draft/Sample search strategy
A draft or sample search strategy of one database should be included in the protocol. The aim of a draft or sample search strategy in the protocol, is to show a search strategy that's a reasonable representation of the final search strategy.
Providing a draft or sample search strategy in the protocol allows for peers to analyse the search strategy. Peers might identify an issue before the review process begins.
If during the review process issues with a search strategy are identified. This can lead to re-evaluating other stages of the review process (e.g., the review question).
Screening, extraction, appraisal
The screening process chosen to outline how studies will be selected into the review from search results by using the selection criteria.
The extraction plan that will be used to determine which data will be extracted from selected studies.
The appraisal method selected outlines how to evaluate the quality of the studies selected in the review and can assess the risk of bias in those studies.
Synthesis
The protocol should outline the process for analysing and synthesising the data that will be made available in the final report.
Remember and reflect
Key takeaway
Follow relevant guidelines for your review type, as they outline what you will need to include in your review protocol.
Please be aware that some protocols will be very short, others, very long and detailed. You need to look at examples to assess what you should include in your protocol.
Consider
It can be helpful to study existing review protocols as an example, before you start developing your own review protocols. Try searching protocol registries for review protocols in a similar area of research.
Review the PRISMA-P checklist when developing your review protocol to ensure that it captures critical elements.