Is it Time to Rethink a Common Approach in the Study of Parent Participation in Parenting Interventions? (Null) Findings from a Large-Scale Cluster Randomised Trial.

The real-world impact of evidence-based parenting programs depends on their ability to engage parents and families. Yet, knowledge about the facilitators and barriers of participation remains limited. A common approach to study parent participation is conducting secondary analyses of clinical trial data, which often yield mixed and inconclusive results. The present study represents one of the largest studies undertaking the secondary analyses approach while addressing key methodological constraints identified in previous research (e.g. low power, narrow sets of predictors). We utilised data collected as part of a cluster randomised trial of a telehealth-delivered Triple P - Positive Parenting Program Seminar Series in Australian primary schools (N = 2272 parents) to assess parent participation. Thirteen participation outcomes were assessed across three domains: registration, seminar attendance, and time spent in sessions. Candidate predictors included child and family demographics, child mental health, parenting and family functioning, and home-school partnership quality. Across 468 exploratory analyses, associations between predictors and participation outcomes were generally small in magnitude, with models explaining only 0.5%-10.3% of the variance in parental participation. After adjustment for multiple comparisons, only one predictor remained statistically significant. These findings highlight the potential limited utility of relying on exploratory secondary analyses of clinical trial data to understand parent participation in parenting programs. Rather than continuing to expand data-driven searches for individual predictors, the field should prioritise theory-driven research and methodological innovations, such as embedding participation experiments within intervention trials.