Background: Evidence and Gap Maps (EGMs) sit within a family of evidence synthesis methods that seek to address broader research questions. EGMs are a valuable tool in which a wider understanding is needed of existing research in a topic area and locating evidence gaps. They do not synthesise existing evidence, but by locating, categorizing, coding, and presenting the evidence in an interactive web based tool, with links to the primary research, they offer a valuable visualisation of existing evidence. Their popularity is growing, and they are particularly valued by policy makers.
Objectives: We undertook a scoping review to address the following questions: 1) What methods are currently used in their development and updating; 2) to what extent do they adhere to recommended guidance; 3) what procedures are in place for updating and maintaining EGMs; and 4) what methods are in place to evaluate the use of web based EGMs.
Methods: We developed a search strategy that included websites as well as database searches. We contacted hosting organisations to locate published EGMs. We used a piloted data extraction table to gather data. We only included EGMs with public facing online maps. We also retrieved any linked or supporting documentation.
Results: We included 96 EGMs addressing a wide range of topics, though they were predominantly in the field of international development, social care, and public health. Their potential in health care is currently less well realised. Approximately 43% did not undertake critical appraisal of the evidence. More than half of the EGMs were not linked to a description of their methodology or information that described the search dates or plans to update the map.
Conclusions: EGMs are an increasingly adopted approach in evidence synthesis and valued by policy makers. They are valuable tools for visualising evidence and highlighting gaps. Yet the guidance for their development is limited, and there is little standardisation in the processes of linking maps to the methods underpinning them. EGM processes must be more transparent and rigorous. Patient, public, and/or healthcare consumer involvement: Extensive consultation with the public on views on EGMs