Graphical representation of the body of the evidence: the essentials for understanding the evidence gap map approach

The significant increase in scientific evidence production has led to the creation of methods to facilitate evidence review and synthesis. This has turned, this has resulted in the emergence of different designs depending on the review’s objective. Evidence gap maps constitute a novel approach for literature review. They are thematic collections of a broad field of evidence, using a systematic search strategy that identifies gaps in knowledge and engages, early on, the target audience to design a friendly graphic product. Evidence maps are a tool to be considered in the roster of options available for research funders in that they are particularly useful for evidence-based decision-making and evidence-based policy development. The most commonly used formats to display the findings of evidence gap search designs are the bubble plot and the intervention-outcome framework. This article corresponds to the sixth of a series of narrative reviews on general topics of biostatistics and clinical epidemiology. The purpose of this review is to describe the principal features of evidence gap maps, highlighting their main objectives and utility, exploring the most commonly used mapping formats, and comparing this approach with other evidence synthesis designs.