Effect-size indices for dichotomized outcomes in meta-analysis.
It is very common to find meta-analyses in which some of the studies compare 2 groups on continuous dependent variables and others compare groups on dichotomized variables. Integrating all of them in a meta-analysis requires an effect-size index in the same metric that can be applied to both types of outcomes. In this article, the performance in terms of bias and sampling variance of 7 different effect-size indices for estimating the population standardized mean difference from a 2 x 2 table is examined by Monte Carlo simulation, assuming normal and nonnormal distributions. The results show good performance for 2 indices, one based on the probit transformation and the other based on the logistic distribution.
Sánchez-Meca
Julio
J
U Murcia, Dept of Basic Psychology & Methodology, Faculty of Psychology, Murcia, Spain. jsmeca@um.es
Marín-Martínez
Fulgencio
F
Chacón-Moscoso
Salvador
S
D000704:Analysis of Variance; D006801:Humans; D016015:Logistic Models; D015201:Meta-Analysis as Topic; D009010:Monte Carlo Method; D011589:Psychology, Experimental / Q000706:statistics & numerical data*; D011594:Psychometrics / Q000706:statistics & numerical data*