'Scoping the scope' of a cochrane review

Systematic reviews use a transparent and systematic process to define a research question, search for studies, assess their quality and synthesize findings qualitatively or quantitatively.A crucial step in the systematic review process is to thoroughly define the scope of the research question.This requires an understanding of existing literature, including gaps and uncertainties, clarification of definitions related to the research question and an understanding of the way in which these are conceptualized within existing literature.This information is often acquired in an ad hoc fashion, however a useful and increasingly popular way to collect and organize important background information and develop a picture of the existing evidence base is to conduct a scoping review.Such reviews may be published as a research outcome in their own right and are appealing since they produce a broad map of the evidence that, if sufficiently transparent and widely available via publication, can be used by many and for applications beyond the authors originally intended purpose.Scoping reviews can inform a systematic review, particularly one with a very broad topic scope, such as those edited by the Cochrane Public Health Group.