A Meta-Analysis of Functional Communication Training for Young Children with ASD and Challenging Behavior in Natural Settings

This meta-analysis synthesized 34 published single-case design studies on functional communication training (FCT) for young children with autism spectrum disorder (ASD). A systematic search of electronic databases and reference lists identified studies published between 1996 and 2021 involving 79 children with ASD aged 2 to 8. Quality evaluation using What Works Clearinghouse standards revealed that only 29.4% of studies met standards with or without reservations, primarily due to insufficient data points per phase. Most studies were conducted in home or school settings with therapists/researchers as primary implementers, followed by parents or caregivers. Low reporting rates were found for preference assessment, treatment fidelity, social validity, and maintenance and generalization effects. Overall, FCT demonstrated large effects for reducing challenging behavior (Tau-BC = 0.97) and moderate-to-large effects for increasing replacement behavior (Tau-BC = 0.78). Moderator analyses revealed significantly larger effect sizes in school versus home settings (p < 0.05). These findings further support FCT as an evidence-based practice for young children with ASD, although methodological rigor must be improved. Future research should systematically evaluate maintenance and generalization effects, develop effective parent training and support strategies, and report intervention dosage parameters to strengthen the evidence base and guide clinical implementation.