"an ideal tool to determine the scope or coverage of a body of literature on a given topic and give clear indication of the volume of literature and studies available as well as an overview (broad or detailed) of its focus. scoping reviews are useful for examining emerging evidence when it is still unclear what other, more specific questions can be posed and valuably addressed by a more precise systematic review."
a scoping review:
answers a broad question
highlights gaps in the literature
may follow a protocol but it doesn't have to be registered
can be used as a tool to determine whether to conduct a systematic review
doesn't usually include risk of bias assessment
doesn't typically include critical appraisal
doesn't need to synthesize the findings of individual studies
make take as long as a systematic review or longer.