biostudies-literatureUnknown10(1)Li XIn meta-analytic studies, there are often multiple moderators available (eg, study characteristics). In such cases, traditional meta-analysis methods often lack sufficient power to investigate interaction effects between moderators, especially high-order interactions. To overcome this problem, meta-CART was proposed: an approach that applies classification and regression trees (CART) to identify interactions, and then subgroup meta-analysis to test the significance of moderator effects. The aim of this study is to improve meta-CART upon two aspects: 1) to integrate the two steps of the approach into one and 2) to consistently take into account the fixed-effect or random-effects assumption in both the the interaction identification and testing process. For fixed effect meta-CART, weights arResearch synthesis methods134-152https://www.ebi.ac.uk/biostudies/studies/S-EPMC6590644biostudies-literatureA flexible approach to identify interaction effects between moderators in meta-analysis.PMC6590644Li XDusseldorp EMeulman JJfalseA flexible approach to identify interaction effects between moderators in meta-analysis.In meta-analytic studies, there are often multiple moderators available (eg, study characteristics). In such cases, traditional meta-analysis methods often lack sufficient power to investigate interaction effects between moderators, especially high-order interactions. To overcome this problem, meta-CART was proposed: an approach that applies classification and regression trees (CART) to identify interactions, and then subgroup meta-analysis to test the significance of moderator effects. The aim of this study is to improve meta-CART upon two aspects: 1) to integrate the two steps of the approach into one and 2) to consistently take into account the fixed-effect or random-effects assumption in both the the interaction identification and testing process. For fixed effect meta-CART, weights ar2019-01-01T00:00:00Z2019 Mar2025-04-04T21:00:09.323Z2019-07-24T07:27:13ZS-EPMC65906443051151410.1002/jrsm.1334