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Systematic reviews

A brief overview of systematic reviews and resources to support producing one.

Review protocols

The plan for a systematic review is called a protocol and defines the steps that will be undertaken in the review.

The Cochrane Collaboration defines a protocol as the plan or set of steps to be followed in a study.

A protocol for a systematic review should describe the rationale for the review, the objectives, the methods that will be used to locate, select, and critically appraise studies, and to collect and analyse data from the included studies.

Higgins J, Thomas J, Chandler J, Cumpston M, Li T, Page MJ et al, editors. Cochrane handbook for systematic reviews of interventions, Cochrane; 2022.

A review protocol will include:

  • Background to the study and the importance of the topic
  • Objectives and scope
  • Selection criteria for the studies
  • Planned search strategy
  • Planned data extraction
  • Proposed method for synthesising the findings.

The protocol will help guide the process of the review and work as a point of reference to each part of the review.

PRISMA is considered the gold standard for reporting how you conducted your systematic review, and it's worth considering these elements now as you prepare your protocol. There is an extension to PRISMA specifically aimed at guiding the format of protocols, PRISMA-P. There is more information about PRISMA in the section of this guide, 'Writing the review'.

Finding existing systematic reviews

In the early stages of your planned project you'll need to check for any existing systematic reviews on the same topic. The section 'Before you build a search' in this guide demonstrates how to do this as part of the scoping searching process. You can also do some searching in the sources listed below for existing reviews. Note that you'll need to keep your eye out for existing systematic reviews as you progress your project and develop more sophisticated searches for your topic.

PubMed: A good place to check for health-related reviews. Use the 'systematic reviews' limit on the left hand side to help you find existing reviews. PubMed will also allow to you find the reviews from the Cochrane Library, and the Joanna Briggs Institute, two well known producers of health related reviews (you could also search those two sites separately if you wish).

PROSPERO: International Prospective Register of Systematic Reviews (health-related). Search PROSPERO to find registered systematic review protocols, i.e. systematic review projects that are currently underway.

The Campbell Collaboration: Campbell systematic reviews follow structured guidelines and standards for summarizing the international research evidence on the effects of interventions in crime and justice, education, international development, and social welfare.

Environmental Evidence Library: contains a collection of Systematic Reviews (SRs) of evidence on the effectiveness human interventions in environmental management and the environmental impacts of humans activities.

EPPI-Centre: Evidence for Policy and Practice Information and Co-ordinating Centre.  (Education and social policy, Health promotion and public health, International health).

You should also consult subject-specific or specialist databases that may be relevant to the topic area. It's worth searching the main databases that you're planning to use for your project for existing systematic reviews. Check the database options to see if you can limit to systematic reviews, or include 'systematic review' in your searches.

Registering your protocol

Registering the protocol for your planned project "promotes transparency, helps reduce potential for bias and serves to avoid unintended duplication of reviews". It's best to wait until your protocol is well developed and unlikely to change before registering it.

Stewart L, Moher D, Shekelle P. Why prospective registration of systematic reviews makes sense. Syst Rev. 2012;1(1):7.

PROSPERO is the main place for registering systematic reviews, rapid reviews and umbrella reviews that have a clear outcome related to human health. The PROSPERO webpage Accessing and completing the registration form has information about how to register your protocol, including information on which review types are eligible. Note that PROSPERO does not accept scoping reviews, and we would recommend registering these with the Open Science Framework.

Open Science Framework is another place that many review protocols are registered. It is a large, free platform dedicated to supporting many aspects of open science and is a good option for scoping reviews or reviews without a health outcome. The OSF Registries area is where protocols can be registered and searched. Information on how to register your protocol is available on the Welcome to Registrations page. Examples of registered protocols may be viewed by searching OSF Registries.

Another way to make your protocol available is to publish it in a journal that accepts protocols. Examples of such journals include Systematic Reviews, BMJ Open, Journal of Human Nutrition & Dietetics and more. To find potential journals, search on the topic of your review using a major database in your discipline and include the words systematic review protocol in your search, e.g. you might search for blended learning education systematic review protocol. The UQ Librarians can also assist you to identify potential journals.