In systematic reviews, what does the sample size refer to?

In the context of systematic reviews, sample size specifically pertains to the number of studies identified that meet the specific inclusion criteria established for the review. Systematic reviews synthesize findings from multiple studies to provide comprehensive insights on a given topic or question. Therefore, when researchers conduct a systematic review, they rigorously search for studies that fit predetermined methodologies, populations, and outcome measures relevant to their research question.

The identification of the number of studies that qualify is crucial because it determines the breadth of evidence available for analysis. A larger number of included studies typically provides a more robust dataset for drawing conclusions and enhances the reliability of the systematic review's findings. In contrast, focusing on the total number of participants surveyed or the extent of data collected does not align with the primary intent of gauging the inclusivity of studies in systematic reviews. Thus, the specific reference to the number of studies as the sample size is accurate and central to the systematic review process.