Scoping reviews often precede a full systematic review. They aim to quickly identify key concepts underpinning the research area, as well as map out the primary sources of potential evidence and their availability. Scoping reviews tend to be conducted where there are few or no systematic reviews in existence in a particular research area, or where an research area is particularly complex or multi-disciplinary.
Tricco, A.C., Antony, J., Zarin, W., Strifler, L., Ghassemi, M., Ivory, J., Perrier, L., Hutton, B., Moher, D. and Straus, S.E. (2015) 'A scoping review of rapid review methods.' BMC Medicine, 13(1) pp. 224.