Which approach is predominantly used in meta-analysis?

The approach predominantly used in meta-analysis is statistical analysis and qualitative review. Meta-analysis is a quantitative research method that integrates findings from multiple studies to arrive at a comprehensive understanding of a particular research question. This method employs statistical techniques to combine data across studies, allowing researchers to assess the overall effect size, evaluate consistency across findings, and identify potential moderating variables.

Incorporating a qualitative review is also vital, as it helps contextualize the statistical results, offering insights into the variations and nuances of the included studies. This combination of statistical analysis with qualitative evaluation enables researchers to draw more robust conclusions than could be made from individual studies alone.

Other methods such as field experiments, qualitative observational methods, and simplistic data collection do not align with the rigorous, integrative approach central to meta-analysis, which focuses on synthesizing existing research through quantitative metrics while considering the broader context through qualitative insights.