Systematic Reviews

Systematic reviews should set clear questions, the answers to which will provide meaningful information that can be used to guide decision-making. These should be stated clearly and precisely in the protocol.

Questions may be extremely specific or very broad, although if broad, it may be more appropriate to break this down into a series of related more specific questions. 

Aids to formulate clear question(s): 

• Science is an iterative process: conducting a scoping search will help to answer any background questions. This knowledge will help to focus the clear still unanswered (foreground) questions
• Structure your query by dividing it into searchable concepts (i.e. make use of a query model like PICO)
• Make use of an experienced information specialist to help formulate questions.  

More detailed information on preparation:  Chapter 1.1 'Getting Started'  in: Systematic Reviews: CRD's guidance for undertaking reviews in health care

The importance of a prospectively registered protocol

Prospectively registering a protocol of a systematic review reduces duplication of effort, research waste, and promotes accountability:

Publication of a protocol for a review that is written without knowledge of the available studies reduces the impact of review authors’ biases, promotes transparency of methods and processes, reduces the potential for duplication, allows peer review of the planned methods before they have been completed, and offers an opportunity for the review team to plan resources and logistics for undertaking the review itself.”

(Source: Cochrane Handbook for Systematic Review Interventions, Version 6.3,2022: Section 1-5) 

Guidance

Where to register

Depending on the type of (systematic) review, there are different places where and how to register a protocol: