Multiple moderator meta-analysis using the R-package Meta-CART

Behavior Research Methods, vol. 52, pp. 2657–2673

Abstract

In meta-analysis, heterogeneity often exists between studies. Knowledge about study features (i.e., moderators) that can explain the heterogeneity in effect sizes can be useful for researchers to assess the effectiveness of existing interventions and design new potentially effective interventions. When there are multiple moderators, they may amplify or attenuate each other's effect on treatment effectiveness. However, in most meta-analysis studies, interaction effects are neglected due to the lack of appropriate methods. The method meta-CART was recently proposed to identify interactions between multiple moderators. The analysis result is a tree model in which the studies are partitioned into more homogeneous subgroups by combinations of moderators. This paper describes the R-package metacart, which provides user-friendly functions to conduct meta-CART analyses in R. This package can fit both fixed- and random-effects meta-CART, and can handle dichotomous, categorical, ordinal and continuous moderators. In addition, a new look ahead procedure is presented. The application of the package is illustrated step-by-step using diverse examples.

Authors 4

1. Xinru Li Aachen Mathematical Institute

   Leiden University

   Affiliation as printed

   Mathematical Institute, Leiden University, P.O. Box 9512, 2300, RA, Leiden, The Netherlands

2. Elise Dusseldorp corresponding Aachen Institute of Psychology, Leiden University

   Leiden University

   Affiliation as printed

   Institute of Psychology, Leiden University, P.O. Box 9555, 2300, RB, Leiden, The Netherlands. elise.dusseldorp@fsw.leidenuniv.nl

   Institute of Psychology, Leiden University, P.O. Box 9555, 2300, RB, Leiden, The Netherlands

3. Xiaogang Su

   The University of Texas at El Paso

   Affiliation as printed

   Department of Mathematical Sciences, University of Texas at El Paso, Austin, TX, 78712, USA

4. Jacqueline J. Meulman Aachen Mathematical Institute

   Leiden University · Stanford University

   Affiliation as printed

   Department of Statistics, Stanford University, Stanford, CA, 94305, USA

   Mathematical Institute, Leiden University, P.O. Box 9512, 2300, RA, Leiden, The Netherlands