Which of the following is a quantitative technique used in some review articles that combines the results of many studies?

Meta-analysis is a quantitative technique that synthesizes the results of multiple studies to provide a clearer statistical understanding of a particular phenomenon or research question. By combining data from various studies, meta-analysis calculates an overall effect size, which enhances the ability to detect patterns, generalize findings, and provide more robust conclusions than any individual study could offer. This method is particularly powerful when studies examine similar hypotheses or outcomes, allowing researchers to effectively summarize existing evidence and draw more comprehensive conclusions about a specific area of inquiry.

The other techniques listed fall into different categories. For example, case study analysis focuses on an in-depth exploration of a single case or a few cases rather than aggregating data across multiple studies. Qualitative synthesis, in contrast, examines themes and patterns in qualitative data without quantitative analysis. A literature review provides a summary and discussion of existing research but does not quantitatively combine results in the same way that a meta-analysis does. Therefore, the defining feature of meta-analysis is its ability to quantitatively combine results, making it a vital tool in research synthesis.