Any good systematic review begins with a protocol outlining the study methodology. According to the National Institutes of Health (NIH), a protocol serves as a road-map for the review and specifies the objectives, methods, and outcomes of primary interest of the systematic review. The purpose of having a protocol is to promote transparency of methods and reduce bias.
According to University of York the review protocol sets out the methods to be used: decisions about the review question, inclusion criteria, search strategy, study selection, data extraction, quality assessment, data synthesis and plans for dissemination.
If modifications to the protocol are required, these should be clearly documented and justified. Modifications may arise from a clearer understanding of the review question, and should not be made because of an awareness of the results of individual studies.
After you write the protocol, you should register it with PROSPERO, an 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. Cochrane protocols are automatically uploaded onto Prospero.
For more details BioMedCentral provides guidelines on publishing protocols.
