Over the past few years, there has been an explosion in the number of systematic reviews conducted and published — although a systematic review is an inappropriate or unnecessary research methodology for answering many research questions. Systematic reviews can be inappropriate for a variety of reasons:

• The topic is too new and there aren't enough relevant published papers to synthesise and analyse for a systematic review
• Many other people have already published systematic reviews on the topic (do a scoping search on the Cochrane Library, or by limiting your search results to systematic reviews on other databases, to see if other systematic reviews exist)
• You do not have enough time to conduct a systematic review (most systematic reviews will take between six to eighteen months on average to complete)
• You do not have any coauthors with whom to conduct the systematic review (systematic review methodology requires two authors to independently screen references to determine which fit pre-defined inclusion criteria)

If you feel your circumstances or research topic match any of the above, a systematic review may not be the best approach for you. You could still do a literature review, and adopt elements of systematic review methodology, rather than a systematic review.

Marshall Dozier, College Lead Librarian at the College of Medicine and Veterinary Medicine at Edinburgh University, has created a presentation called Literature Reviews: Functions, Types and Methods (link opens in new window):

When we think of a literature review, we often forget to consider the different types of reviews and the different roles or functions that literature reviews can have.

In this short presentation I will first discuss some functions of literature reviews, and then make some points about how the function or purpose of your review should inform the type that you choose to do, and the methods that you employ.

There are many types of systematic review, they each have a slightly different purpose and methodology.

• Rapid review: narrow, quick search and assessment of very specific question
• Scoping review : assessment of potential size/scope of available literature
• Integrative review: includes qualitative/quantitative/ theory
• Umbrella review: review of systematic reviews

For details of other review types see

Grant M, Booth A. A typology of reviews: an analysis of 14 review types and associated methodologies (link opens in new window). Health Information & Libraries Journal. 2009;26(2):91-108.

Andrea Tricco at Knowledge Synthesis has developed What Review is Right for You? (link opens in new window), an online tool 'designed to provide guidance and supporting material to reviewers on methods for the conduct and reporting of knowledge synthesis.' The tool currently only supports quantitative studies. Researchers can fill in a questionnaire, and it will suggest an appropriate review type, and resources to support the review.