Generalization
The findings reported in this meta-analysis can generalize to children with a developmental disability. There are some
factors contributing to the generalizability of the results of this meta-analysis. First, the studies included in this meta-
analysis represented PMTs conducted in four countries – The United States, Australia, Ireland, and China. Half of the studies,
however, were located in Australia, and 90% were located in ‘‘Western’’ societies. Generalizing the effects of PMT on child
behavior, therefore, still may not be practical to non-Western cultures.
Second, the evidence in this meta-analysis indicates that, although PMT was originally developed for children with
conduct disorder related behaviors (Kazdin, 1997), PMT also appears to have an effect on disruptive behaviors related to
developmental disabilities. The implication of the moderate effect size of PMT on the behavior with children with a
developmental disability is encouraging because of the chronic and generally more severe disruptive behaviors related to
developmental disabilities.