A scoping review is generally addressing an exploratory research question and is taking a broad view of a body of research, focused on getting an idea of the key concepts thus far explored, and any gaps in the current body of literature. According to Pham, et. al. 2014, "The scoping review has become an increasingly popular approach for synthesizing research evidence (Davis et al., 2009; Levac et al., 2010; Daudt et al., 2013). It aims to map the existing literature in a field of interest in terms of the volume, nature, and characteristics of the primary research (Arksey and O'Malley, 2005). A scoping review of a body of literature can be of particular use when the topic has not yet been extensively reviewed or is of a complex or heterogeneous nature (Mays et al., 2001). They are commonly undertaken to examine the extent, range, and nature of research activity in a topic area; determine the value and potential scope and cost of undertaking a full systematic review; summarize and disseminate research findings; and identify research gaps in the existing literature (Arksey and O'Malley, 2005; Levac et al., 2010). As it provides a rigorous and transparent method for mapping areas of research, a scoping review can be used as a standalone project or as a preliminary step to a systematic review (Arksey and O'Malley, 2005)."*
Scoping review share a number of methodological similarities with systematic reviews, but there are also key differences in both method and goals for the two types of reviews. Both types of reviews use transparent and systematic methodology intended to identify and analyze all literature relevant to a given research question, but systematic reviews are generally attempting to answer a more focused research question while scoping review are usually answering broader research questions (usually mapping the complete body of literature pertaining to a particular topic area) and thus generally have more expansive search parameters and include more diverse study designs and methodologies. Lastly, as scoping reviews intend to provide only a descriptive overview of a research area, rather than a critical assessment, generally a risk of bias assessment does not need to be conducted on individual studies included in the analysis.
*Pham MT, Rajić A, Greig JD, Sargeant JM, Papadopoulos A, McEwen SA. A scoping review of scoping reviews: advancing the approach and enhancing the consistency. Res Synth Methods. 2014 Dec;5(4):371-85. doi: 10.1002/jrsm.1123. Epub 2014 Jul 24. PMID: 26052958; PMCID: PMC4491356.