We examined mediators and moderators of change in conduct problems, in a multiagency randomized trial of the Incredible Years parenting program. Preschoolers (n = 153) at risk for conduct problems were randomly assigned to intervention (n = 104) and wait-list (n = 49) groups. Boys and younger children, and those with more depressed mothers, tended to show greater improvement in conduct problems post-intervention. Other risk factors (i.e., teen or single parenthood, very low income, high initial levels of problem behavior) showed no predictive effects, implying intervention was at least as successful at helping the most disadvantaged families, compared to more advantaged. Mediator analyses found change in positive parenting skill predicted change in conduct problems.

Objective To evaluate the effectiveness of a parenting programme as a preventive intervention with parents of preschool children considered to be at risk of developing conduct disorder.Design Pragmatic randomised controlled trial using a block design with allocation by area.Setting Eleven Sure Start areas in north and mid-Wales.Participants 153 parents from socially disadvantaged areas, with children aged 36-59 months at risk of conduct disorder defined by scoring over the clinical cut off on the Eyberg child behaviour inventory. Participants were randomised on a 2:1 basis, 104 to intervention and 49 to remaining on the wait listing (control). Twenty (13%) were lost to follow-up six months later, 18 from the intervention group.Intervention The Webster-Stratton Incredible Years basic parenting programme, a 12 week group based intervention.Main outcome measures Problem behaviour in children and parenting skills assessed by self reports from parents and by direct observation in the home. Parents' self reported parenting competence, stress, and depression. Standardised and well validated instruments were used throughout.Results At follow-up, most of the measures of parenting and problem behaviour in children showed significant improvement in the intervention group. The intention to treat analysis for the primary outcome measure, the Eyberg child behaviour inventory, showed a mean difference between groups of 4.4 points (95% confidence interval 2.0 to 6.9, P<0.001) on the problem scale with an effect size of 0.63, and a mean difference of 25.1 (14.9 to 35.2, P<0.001) on the intensity scale with an effect size of 0.89.Conclusion This community based study showed the effectiveness of an evidence based parenting intervention delivered with fidelity by regular Sure Start staff. It has influenced policy within Wales and provides lessons for England where, to date, Sure Start programmes have not been effective.Trial registration ISRCTN46984318

Objective To investigate the cost effectiveness of a parenting programme. Design An incremental cost effectiveness analysis alongside a pragmatic randomised controlled trial of the effectiveness of a group parenting programme delivered through Sure Start in the community.Setting Sure Start areas in north and mid Wales.Participants Parents of 116 children aged 36-59 months (87% of the clinical sample) at risk of developing conduct disorders defined by scoring over the clinical cut off on the Eyberg child behaviour inventory). Children were identified by health visitors and recruited by the research team.Intervention The Webster-Stratton Incredible Years basic parenting programme or a six month waiting list control.Main outcome measure Incremental cost per unit of improvement on the intensity score of the Eyberg child behaviour inventory.Results The bootstrapped incremental cost effectiveness ratio point estimate was £73 (€109, $142) per one point improvement on the intensity score (95% confidence interval £42 to £140). It would cost £5486 (€8190, $10 666) to bring the child with the highest intensity score to below the clinical cut-off point and £1344 (€2006, $2618) to bring the average child in the intervention group within the non-clinical limits on the intensity score (below 127). For a ceiling ratio of £100 (€149, $194) per point increase in intensity score, there is an 83.9% chance of the intervention being cost effective. The mean cost per child attending the parenting group was £1934 (€2887, $3760) for eight children and £1289 (€1924, $2506) for 12 children, including initial costs and materials for training group leaders. When we categorised the sample into relatively mild, moderate, and severe behaviour groups based on intensity scores at baseline the intervention seemed more cost effective in those with the highest risk of developing conduct disorder.Conclusion This parenting programme improves child behaviour as measured by the intensity score of the Eyberg child behaviour inventory at a relatively low cost and was cost effective compared with the waiting list control. This parenting programme involves modest costs and demonstrates strong clinical effect, suggesting it would represent good value for money for public spending.

Background: Parenting programs aim to reduce children's conduct problems through improvement of family dynamics. To date, research on the precise benefits and possible harms of parenting programs on family well‐being has been unsystematic and likely to be subject to selective outcome reporting and publication bias. Better understanding of program benefits and harms requires full disclosure by researchers of all included measures, and large enough numbers of participants to be able to detect small effects and estimate them precisely. Methods: We obtained individual participant data for 14 of 15 randomized controlled trials on the Incredible Years parenting program in Europe (total N  =   1,799). We used multilevel modeling to estimate program effects on 13 parent‐reported outcomes, including parenting practices, children's mental health, and parental mental health. Results: Parental use of praise, corporal punishment, threats, and shouting improved, while parental use of tangible rewards, monitoring, or laxness did not. Children's conduct problems and attention deficit hyperactivity disorder (ADHD) symptoms improved, while emotional problems did not. Parental mental health (depressive symptoms, self‐efficacy, and stress) did not improve. There was no evidence of harmful effects. Conclusions: The Incredible Years parenting program improves the aspects of family well‐being that it is primarily designed to improve: parenting and children's conduct problems. It also improves parent‐reported ADHD symptoms in children. Wider benefits are limited: the program does not improve children's emotional problems or parental mental health. There are no signs of harm on any of the target outcomes.