According to Booth (2016), "a mapping review aims at categorizing, classifying, characterizing patterns, trends or themes in evidence production or publication" (p. 14). Grant & Booth (2009) add that the point in conducting a mapping review is to "map out" and thematically understand the pre-existing research on a particular topic including assessing any gaps that could be addressed by future research. 

Mapping reviews are not to be confused with scoping reviews and differ as the outcome of a mapping review can be to produce primary research or more reviews. Mapping reviews are also known as systematic maps.

When to Use It: Booth (2016) states that "a mapping review is best used where a clear target for a more focused evidence product has not yet been identified" (p. 14). Mapping reviews are especially useful for topics where there is a lot of preexisting literature, for investing if there are gaps in the literature, and are useful to conduct before larger knowledge syntheses such as a systematic review.

The following characteristics, strengths, and challenges of conducting mapping reviews are derived from Grant & Booth (2009) and Cooper (2016). 

Characteristics:

• Although mapping reviews are sometimes called scoping reviews, the key difference is that mapping reviews focus on a review question, rather than a topic

• Mapping review searches are often quick and are intended to provide a broad overview

• Mapping reviews can take different approaches in what types of literature is focused on in the search

Strengths:

• Allows you to map out the literature on a topic which lets you see gaps in the literature

• An useful tool for policymakers, practitioners and researchers by providing "an explicit and transparent means of identifying narrower policy and practice-relevant review questions" (Grant and Booth, 2009, p. 97).

Challenges:

• Time-constrained

• Do not involve synthesis and analysis as with other knowledge syntheses

• Broad nature of the search process can leave some articles out

• Tend to describe studies on a broader level which can "oversimplify the picture or mask considerable variation (heterogeneity) between studies and their findings" (Grant and Booth, 2009, p. 98)

• Often exclude quality assessment and "[characterize] studies only on the basis of study design" (Grant and Booth, 2009, p. 98)

The following resource provides further support on conducting a mapping study:

METHODS & CONDUCT

• Centre for Evidence-Based Conservation Bangor University, UK. (2013). Guidelines for Systematic Reviews in Environmental Management.

• Cooper I. D. (2016). What is a "mapping study?" Journal of the Medical Library Association: JMLA, 104(1), 76–78. 

• Miake-Lye, I.M., Hempel, S., Shanman, R. & Shekelle, P.G. (2016). What is an evidence map? A systematic review of published evidence maps and their definitions, methods, and products. Systematic Reviews 5(28).

SUPPLEMENTARY RESOURCES

Check out the supplementary resources page for additional information, including articles, on mapping reviews.