Skip to Main Content

Systematic reviews

A quick guide to introduce you to systematic reviews

Review types

The methodology for systematic reviews is designed to be rigorous and isn't suitable for individual researchers and those working to a tight timescale. To learn more about different review methodologies and understand which type of review will best to undertake for your topic, we recommend you read ths following article: 

Grant, M.J. and Booth, A. (2009), A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26: 91-108. doi:10.1111/j.1471-1842.2009.00848.x


Is there sufficent literature on your topic to warrant a review?


As systematic reviews synthesise existing evidence and provide synthesis of published studies, it is a requirement that there is sufficent literature available on a topic for a review to be successful. You can carry out a scoping search (background search to assess the amount of literature available) before deciding on the best type of review to address your research question. If you find there isn't much literature available on your topic then you may decide to conduct a 'systematic search and review' which aims to combine the strengths of the more traditional critical review with a systematic search process.

Do you have the time to complete a systematic review?


Systematic reviews of medical interventions are carried out over a long period of time (mean: 67.3 weeks) and good quality, rigorous systematic reviews require multiple authors and experts to support the different stages of the review process.

Reviewers should search multiple bibliographic databases (at least three relevant databases) to ensure that they have been comprehensive in their approach, and utilise other searching methods such as hand-searching to ensure all trials, or relevant studies are identified. Hand-searching is a manual process whereby an author identifies relevant studies for the review by examining citation lists in journal issues or in grey literature. The search process can be time consuming, so if you are on a tight deadline a different type of review methodology is likely to more appropriate. 

Do you have methods to reduce the risk of bias in place?


Systematic reviews follow a study protocol which details the methods that will be used in the review. Protocols are essential to ensuring a rigorous approach and can help verify that previous systematic reviews have not already answered the research question.

Do you have support available to work on the review?


Systematic reviews should not be carried out by one person as this may lead to increased bias in searching, screening and data selection. A second person should be available for screening and article selection and this will reduce the chance of any errors made.

Well conducted systematic reviews are carried out by teams with expertise in the topic under review, with the support of information professionals (librarians or information specialists) advising on the search strategy, database selection and reporting methods. If you are a current student, our team of librarians can advise you on good practice for search strategy formation and provide advice on searching databases efficiently. They will not be able to check your search strategy, or help you generate keywords as your search strategy will be assessed as part of your academic work.

There are many other types of review that you can undertake and often these are defined by the amount of time you have and the amount of literature that is available. Scoping reviews are often used to clarify gaps in knowledge or assess the literature available on a given topic. Sometimes, they can be used to determine if a systematic review is necessary. This article provides information to help you understand the differences between these review types:

Munn, Z., Peters, M.D.J., Stern, C. et al. Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Med Res Methodol 18, 143 (2018).

You may find our guide on scoping reviews helpful.

Contact Us or Give Feedback