Before you begin your systematic review, you should write a review protocol. Protocols are important for the following reasons:
- To promote transparency of methods by specifying the objectives, methods, and outcomes of primary interest of the systematic review before conducting the systematic review. This is to set expectation/roadmap to meet the review objective.
- To avoid unplanned duplication as to inform others that a review on your topic is on-going so that it will not be duplicated. The main author should be contactable by another team who is interested to conduct a systematic review if the review has not been updated after sometime since the protocol was last registered.
- To minimise the risk of bias in systematic review due to ad-hoc decisions made during the synthesis process. Specifying inclusion and exclusion criteria for the study selection as well as data extraction criteria in the protocol. This will make the review process as rigorous, and transparent, as possible.
You can refer to PRISMA-P (PRISMA for Systematic Review Protocols) which is the standard for writing a protocol.
The Prisma-P is an extension of the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). It consists of 17-item checklist published in January 2015 for developing review protocols.
Steps for writing a review protocol:
- Review question and objective
- Setting criteria for inclusion and exclusion
- Inclusion criteria – puts the question into operation (population, intervention or comparison, outcome, study design, language, publication)
- Exclusion criteria certain studies e.g. specific populations, language, setting
- Specify the methods use in:
- Identify research evidence
- Select studies for inclusion
- Data extraction
- Quality assessment
- Synthesise results
- Disseminate the review findings