Protocols in systematic reviews serve a number of purposes. Firstly, they help the researchers to clarify for themselves what their procedures will be and to worth through as potential difficulties ahead of time as possible. Secondly, if protocols are pre-registered before the research formally begins, they can help to reduce bias in the research and increase transparency. Readers will be aware of any later deviations from the methodology, which the researchers will need to justify. Lastly, pre-registration may reduce duplication of research if other researchers can see that a review is already ongoing in their area.
Generally, protocols are intended to lay out the reason for the research proposed, any relevant hypotheses and a proposed methodology for conducting the review.
Protocols generally include: