What are scoping reviews? Providing a formal definition of scoping reviews as a type of evidence synthesis.

Evidence synthesis encompasses a broad range of review types, and scoping reviews are an increasingly popular approach to synthesizing evidence in a number of fields. They sit alongside other evidence synthesis methodologies, such as systematic reviews, qualitative evidence synthesis, realist synthesis, and many more. Until now, scoping reviews have been variously defined in the literature. In this article, we provide the following formal definition for scoping reviews: Scoping reviews are a type of evidence synthesis that aims to systematically identify and map the breadth of evidence available on a particular topic, field, concept, or issue, often irrespective of source (ie, primary research, reviews, non-empirical evidence) within or across particular contexts. Scoping reviews can clarify key concepts/definitions in the literature and identify key characteristics or factors related to a concept, including those related to methodological research.