| In this meta-analysis, the researcher collected published and unpublished play therapy outcome studies, separated them into two categories (subjects under seven years and subjects seven years and older), and coded them on variables such as sample size, outcome measures used, subject age, sex, and presenting problem, experience of therapist, parent involvement, type of play therapy, and number of sessions delivered. Both comparative (between-group) and pretreatment-posttreatment effect sizes were computed. An overall between-group effect size of .18 was obtained, suggesting that there is not currently enough evidence to conclude that play therapy is an effective treatment for young children and more effective than non-play interventions. Play therapy was not found to be more effective with children under seven years of age than older children at more advanced cognitive levels. Cognitive Behavioral Play Therapy and play therapy with behavioral components were not shown to be more effective than other play therapy approaches. Congruent with the literature, group and individual play therapy were found to be equally effective, outcome measures from observers and therapists resulted in higher effect sizes, and teacher ratings and child self-report measures resulted in lower effect sizes (although not a significant difference). Several hypotheses could not be tested due to a lack of information provided in the original studies. Researchers tended to report limited information on subject, therapist, and therapy characteristics. Presenting problems were often not well-defined, tending to be vague or general. Many studies could not be used because they were poorly designed, the authors provided insufficient statistical information or used participants spanning a wide range of ages. In this meta-analysis, I demonstrated that many of the existing play therapy outcome studies are seriously flawed and that more studies of greater scientific rigor need to be done before play therapy can be considered an empirically validated treatment. School psychologists are uniquely positioned to conduct single-case studies within the natural environment of the school. If the effectiveness of play therapy can be demonstrated to school administrators and professionals as well as parents, it is likely that more children will benefit from this service. |
