Systematic reviews and scoping reviews both use transparent and reproducible methods to synthesize evidence. However, the purpose of a scoping review is quite different than that of a systematic review, and so are several steps in the scoping review process. These differences include:
The research question(s)
Systematic reviews evaluate effectiveness or cost-effectiveness of interventions, or prevalence, incidence, or etiology of a disease. A typical research question might be:
- What is the cost-effectiveness of blood glucose self-monitoring in type 2 diabetes mellitus in high-income countries?
Scoping reviews describe, rather than evaluate, literature. A scoping review may clarify a key research concept or describe characteristics of studies addressing a particular research topic. Research questions might include:
- How is the concept of “rehabilitation potential” defined in studies of individuals with acquired brain injuries?
- What are the major components of fatigue management interventions offered to adult patients with multiple sclerosis?
Assessment of biases
A critical step in systematic reviews is assessing risk of bias in included studies, and then assessing if the data synthesis itself may be biased due to missing results (meta-bias).
Scoping reviews do not analyze study outcomes, so they typically don’t include bias assessments. If an assessment is included, a rationale for doing so and details on the method of assessment must be provided.
Data synthesis
Systematic reviews include statistical synthesis (meta-analysis or other summary of effect estimates). A summary of findings table, containing effect magnitudes and judgements of the overall quality of evidence, is also provided.
Scoping reviews do not require effect estimates or meta-analysis, but may use basic qualitative analysis. The data of interest is categorized and presented in charts, accompanied by a narrative summary. For example, a scoping review of “rehabilitation potential” notes:
“Two different uses of the term rehabilitation potential can be found. First, rehabilitation potential continued to be used in reference to a prediction of the extent to which a patient is likely to improve with rehabilitation interventions….The second use of rehabilitation potential in documents published in the last two decades relates to patients’ actual performance (or outcome) following rehabilitation interventions.” (Shun, Swaine, Bottari, 2020, page 820).
Interested in learning more? The HSLS Systematic Review Program Guide has additional articles on scoping review methods.
~Mary Lou Klem