This study aimed at evaluating the effectiveness of parent management training programs that assisted parents of
children with developmental disabilities in reducing children’s disruptive behaviors. Using random effects model, the main
effects of this meta-analysis indicated that, among the 11 randomized clinical trial effect sizes included, PMT programs have
a positive and significant effect on the behavior of children with a developmental disability. The effect g = 0.32 is in the
moderate range (Cohen, 1988). This result, although not quite as large, is not dissimilar from the effect of Tellegen and
Sanders’ (2013) meta-analysis of Stepping Stones Triple P1 (d = 0.54). As noted previously, the Tellegen and Sanders meta-
analysis is the only meta-analysis to date that examines the effects of PMT on the behavior of children with a developmental
disability.