The effectiveness of the Incredible Years pre-school parenting programme in the United Kingdom: a pragmatic randomised controlled trial

This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this record.The prognosis for children with early-onset conduct disorder is poor. Conduct disorder also has a social cost for families and communities, and an economic cost for society through the increased use of health, education, social, legal and detention services. In this study, the Incredible Years (IY) BASIC programme was delivered to parents of pre-school children at risk of developing a conduct disorder and evaluated by pragmatic randomised controlled trial. Participants were parents of 161 children (110 intervention, 51 control) aged between 36 and 59 months (mean age 44 months, 63% boys) and scoring over the clinical cut-off on the Strengths and Difficulties Questionnaire (SDQ). At follow-up (six months post-baseline), the intent-to-treat analysis showed a mean between group difference in favour of IY on the SDQ total difficulties score of 2.23 (p < 0.05, effect size: 0.50). IY was also superior to control on the Eyberg Child Behaviour Inventory (p < 0.05, effect size: 0.37) and on the Arnold and O’Leary parenting scale (p < 0.01, effect size: 0.43). This study confirms the effectiveness of IY in a public system delivered with fidelity by regular children’s centre staff, supporting findings from a similar trial in Wales. These results support the wider roll-out of IY to similar children.The authors would like to acknowledge the hard work and dedication of Birmingham City Council’s “Brighter Futures” team, including the facilitators who ran parent groups and collected fidelity data, and Judy Hutchings, who oversaw the implementation of IY and provided supervision to the group leaders. Michael Little was the project Chief Investigator. The authors thank the parents who took part in the trial, contributing valuable data on their children’s well-being. The North Wales Trials Unit (NWORTH) provided the randomisation service for this study. Pat Linck provided invaluable assistance to Rhiannon Tudor Edwards on the cost-effectiveness study. Vashti Berry’s time is supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care South West Peninsula (PenCLAHRC), and Tracey Bywater and Sarah Blower are part of the Healthy Children Healthy Families Theme of the NIHR CLAHRC Yorkshire and Humber. The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health