Meta-analysis. A quantitative approach to research integration.

Meta-analysis is being used with increasing frequency in clinical medicine as an attempt to improve on traditional methods of narrative review by systematically aggregating information and quantifying its impact. Combining data from several studies using meta-analysis can increase statistical power, provide insight into the nature of relationships among variables, and increase generalizability of results more rigorously than less quantitative review methods. Like all review methods, meta-analysis can be limited by sampling bias, inadequate data, and biased outcome interpretation. Still, the advantages noted above make meta-analysis a methodology that warrants testing and empirical evaluation.