BACKGROUND: Interventions to promote positive parenting are often reported to offer good outcomes for children but they can consume substantial resources and they require rigorous appraisal.

METHODS: Evaluations of the Triple P parenting program were subjected to systematic review and meta-analysis with analysis of biases. PsychInfo, Embase and Ovid Medline were used as data sources. We selected published articles reporting any child-based outcome in which any variant of Triple P was evaluated in relation to a comparison condition. Unpublished data, papers in languages other than English and some book chapters were not examined. Studies reporting Eyberg Child Behavior Inventory or Child Behavior Checklist scores as outcomes were used in the meta-analysis.

RESULTS: A total of 33 eligible studies was identified, most involving media-recruited families. Thirty-one of these 33 studies compared Triple P interventions with waiting list or no-treatment comparison groups. Most papers only reported maternal assessments of child behavior. Twenty-three papers were incorporated in the meta-analysis. No studies involved children younger than two-years old and comparisons of intervention and control groups beyond the duration of the intervention were only possible in five studies. For maternally-reported outcomes the summary effect size was 0.61 (95%CI 0.42, 0.79). Paternally-reported outcomes following Triple P intervention were smaller and did not differ significantly from the control condition (effect size 0.42 (95%CI -0.02, 0.87)). The two studies involving an active control group showed no between-group differences. There was limited evidence of publication bias, but there was substantial selective reporting bias, and preferential reporting of positive results in article abstracts. Thirty-two of the 33 eligible studies were authored by Triple-P affiliated personnel. No trials were registered and only two papers contained conflict of interest statements.

CONCLUSIONS: In volunteer populations over the short term, mothers generally report that Triple P group interventions are better than no intervention, but there is concern about these results given the high risk of bias, poor reporting and potential conflicts of interest. We found no convincing evidence that Triple P interventions work across the whole population or that any benefits are long-term. Given the substantial cost implications, commissioners should apply to parenting programs the standards used in assessing pharmaceutical interventions. See related commentary: http://www.biomedcentral.com/1741-7015/10/145.