The Effectiveness of the Incredible Years Program for Children with ADHD: A Meta-Analysis

Purpose : The Incredible Years (IY) Program is an umbrella framework that includes various early intervention programs designed for different target groups. Implemented in 36 states across the United States since 1984, the program has also been applied to children who have been diagnosed with Attention-Deficit/Hyperactivity Disorder (ADHD). Method : Using the meta-analysis technique, the effect size of the Incredible Years (IY) Program was calculated based on overall and moderator variables. Searches were conducted in six different databases, and experimental studies published between 2000 and 2024 that implemented the program with children diagnosed with ADHD were included. The studies were examined for publication bias and heterogeneity, and effect sizes were computed through fixed-effect model and random-effects model. Results : The meta-analysis included 18 studies. Most of these studies were published articles, involved children aged 4–6, and implemented a 20-week intervention period. The included studies were significant under both fixed-effect model and random-effects model. The fixed-effect model yielded a weak effect size with a point estimate of 0.169, while the random-effects model revealed a small effect size with a point estimate of 0.383. The analysis revealed a high and statistically significant level of heterogeneity. Results from multiple publication bias tests suggested no evidence of publication bias. Intervention duration and year of publication were not found to have an effect in the analyses of effect size, whereas age groups, measurement instruments, and type of publication showed an effect. Conclusion : The analysis demonstrated that the Incredible Years (IY) Program proves to be effective for children diagnosed with ADHD. Accordingly, the use of the program with children diagnosed with ADHD is recommended. Implications for Rehabilitation : Considering the limited yet positive impacts of the IY Program on children with ADHD, its implementation could be expanded by providing training to staff working in rehabilitation centers. Furthermore, the program may serve as a supplementary intervention for children who have developmental disabilities receiving education or therapy, thereby offering additional support for their development.