What method is used to aggregate data from multiple studies to reach a conclusion?

The method used to aggregate data from multiple studies to reach a conclusion is known as a meta-analysis. This statistical technique pools data from various independent studies to provide a comprehensive overview of research findings on a specific topic. By combining results, a meta-analysis can enhance the statistical power, offering a clearer picture of effects and associations, which might not be apparent in individual studies alone. This approach allows researchers to assess the consistency and strength of evidence across different studies, thereby providing a more robust conclusion regarding the subject under investigation.

In contrast, the other options serve different purposes. Qualitative research focuses on non-numerical data, exploring concepts, experiences, or meanings, which differs fundamentally from aggregating quantitative data. A systematic review, while it involves a thorough literature search and may summarize findings, does not necessarily include the statistical aggregation of data that characterizes meta-analysis. Case studies, on the other hand, involve an in-depth examination of a single subject or group, limiting their application in drawing broader conclusions from multiple studies.