Literature review papers: the search and selection process

In an earlier publication (Van Wee & Banister, 2016), we explained that literature review papers (LRP) should explicitly report on the search and selection process of documents included. In this paper, we present two approaches for reporting the methodology for doing this: a basic approach and a reasoned approach. The basic approach includes reporting databases(s), keywords, search strings, snowballing, the selection of documents, presenting an overview of documents included and reporting additional selection criteria (if applicable). The reasoned approach adds to the basic approach (what was done) by explicitly explaining the motivation for choices and showing the selection process graphically (why it was done). The two approaches should be seen as options, and not the only alternatives. We recommend that authors of LRPs depart from these approaches and modify them where appropriate. The important lesson is that authors should be explicit about the approach adopted, as this enables the reader to understand the thinking behind the LRP and the conclusions drawn.