Study Preregistration: Individual Participant Data Meta-Analysis: Individual Differences in Mediators of Parenting Program Effects on Disruptive Behavior.

Parenting programs are the most widely used strategy to prevent and reduce children's disruptive behavior,1 and yet we know very little about what exact changes in parenting behavior underlie program effects on disruptive child behavior. In fact, most studies have been unable to identify any mediators of parenting program effects.2 This is likely because, at least in part, individual trials tend to be underpowered to detect mediation effects,3 and are unable to take the known heterogeneity in program effects4 into account.