Conduct problems are the most common reason for referral for psychological and psychiatric treatment in childhood. The prevalence rate of conduct disorder is 5?10%. It can lead to negative life outcomes including criminal behaviour and psychiatric disorders, with increased costs to the education, health, social and criminal justice services. The study involved an evaluation of an universal school-based approach ? the Incredible Years Teacher Classroom Management programme ? which was developed in the US and implemented in Jamaica to help reduce conduct problems in young children.