Moderators of an intervention on emotional and behavioural problems: household- and school-level parental education.

Background: Children of lower-educated parents and children in schools with a relatively high percentage of peers with lower-educated parents (lower parental education schools) are more likely to develop emotional and behavioural problems compared to children in higher-educated households and schools. Universal school-based preventive interventions, such as the Good Behaviour Game (GBG), are generally effective in preventing the development of emotional and behavioural problems, but information about potential moderators is limited. This study examined whether the effectiveness of the GBG in preventing emotional and behavioural problems differs between children in lower- and higher-educated households and schools.

Methods: Using a longitudinal multi-level randomized controlled trial design, 731 children (Mage=6.02 towards the end of kindergarten) from 31 mainstream schools (intervention arm: 21 schools, 484 children; control arm: 10 schools, 247 children) were followed annually from kindergarten to second grade (2004-2006). The GBG was implemented in first and second grades.

Results: Overall, the GBG prevented the development of emotional and behavioural problems. However, for emotional problems, the GBG-effect was slightly more pronounced in higher parental education schools than in lower parental education schools (Bhigher parental education schools =-0.281, P <0.001; Blower parental education schools =-0.140, P = 0.016). No moderation by household-level parental education was found.

Conclusions: Studies into universal school-based preventive interventions, and in particular the GBG, should consider and incorporate school-level factors when studying the effectiveness of such interventions. More attention should be directed towards factors that may influence universal prevention effectiveness, particularly in lower parental education schools.