Individual participant data (IPD) meta-analyses of randomised trials are considered a reliable way to assess participant-level treatment effect modifiers but may not make the best use of the available data. Traditionally, effect modifiers are explored one covariate at a time, which gives rise to the possibility that evidence of treatment-covariate…

Although there is robust evidence of the benefits of attachment-based parenting interventions, limited research has examined their impact on dyadic mutuality and toddler behavior problems. Given the central question in prevention research of what works for whom, and the documented relation of maternal psychological risk to parenting and…