Measuring Study-Specific Heterogeneity in Meta-Analysis: Application to an Antecedent Biomarker Study of Alzheimer's Disease.

TLDR: This article proposes several new indices that measure the heterogeneity for individual studies in a meta-analysis that can be regarded as a generalization of the collective index of heterogeneity in meta-analyses proposed by various authors.

Abstract: This article proposes several new indices that measure the heterogeneity for individual studies in a meta-analysis. These indices directly assess how inconsistent an individual study is compared to the rest of studies used in the meta-analysis, that is, how much impact the specific study has on the scientific conclusion of the meta-analysis and further on the generalization of the conclusion. The proposed indices can be intuitively interpreted as the proportion of total variance from all studies in a meta-analysis that can be accounted for by the heterogeneity from specific studies. Further, each proposed index over all the studies sums to the collective measure of heterogeneity for the meta-analysis. Therefore our proposed study-specific indices of heterogeneity can be regarded as a generalization of the collective index of heterogeneity in meta-analyses proposed by various authors. We examine the difference among the proposed study-specific measures of heterogeneity and assess the variation associated w...