Heterogeneity in meta-analyses: an unavoidable challenge worth exploring

Heterogeneity is a critical but unavoidable aspect of meta-analyses that reflects differences in study outcomes beyond what is expected by chance. These variations arise from differences in the study populations, interventions, methodologies, and measurement tools and can influence key meta-analytical outputs, including pooled effect sizes, confidence intervals, and overall conclusions. Systematic reviews and meta-analyses combine evidence from diverse studies; thus, a clear understanding of heterogeneity is necessary for reliable and meaningful interpretations of the results. This review examines the concepts, sources, measurement techniques, and implications of this heterogeneity. Statistical tools (e.g.,…