The programme developed by Professor Carolyn Webster-Stratton had produced a significant level of research to suggest that it is the best way to treat early onset conduct disorders by teaching parents to change their behaviour which in turn changes their child's behaviour (social learning theory). In Essex 296 parents have taken part in groups and self completed questionnaires have shown an improvement in all the following areas; family life, parent-child relationship, level child problem behaviours, frequency of child problem behaviours, strengths and difficulties, parental stress and general health. This shows that the Incredible Years Parent Training Program is a success.