A protocol outlines your objectives, planned methodology, and eligibility criteria. While not all publishers require a registered protocol, setting one is best practice for Scoping Reviews. A priori protocols also provide the added benefit of helping to outline the full process in advance so that you have a plan to follow. 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. That said, there is more flexibility in adjusting your protocol and especially your eligibility criteria once you have already begun screening.
Note: elements may vary by discipline
Example
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.
As part of your Protocol, you will want to consider if you have an appropriately sized team of researchers for conducting a Scoping Review. Disciplines vary on team size expectations, however there are some general best practices that you may want to consider.
Establishing team member roles in advance is extremely beneficial for smoothly conducting and documenting the review process.
"As with all well-conducted systematic reviews, an a priori protocol must be developed before undertaking the scoping review. A scoping review protocol is important, as it pre-defines the objectives, methods, and reporting of the review and allows for transparency of the process. The protocol should detail the criteria that the reviewers intend to use to include and exclude sources of evidence and to identify what data is relevant, and how the data will be extracted and presented. The protocol provides the plan for the scoping review and is important in limiting the occurrence of reporting bias. Any deviations of the scoping review from the protocol should be clearly highlighted and explained in the scoping review."
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