Disruptive Child Behaviors, Parent-Training, and Income Inequality: A Quasi-Experimental Design Combining Survey and Registry Data for Long-Term Insights

Background: Disruptive child behaviors, characteristic of prevalent disorders such as ADHD, ODD, and CD, are linked to significant strain on families. Examinations of how evidence-based parent-training programs may mitigate or buffer against such long-term strain are sparse.<br/><br/>Aims: We aimed to examine economic inequality and long-term spill-over effects of the Incredible Years parent-training program on family income among Danish families with disruptive child behavior problems.<br/><br/>Methods: We used a quasi-experimental design, comparing a a large Danish effectiveness sample of families (n = 707) who had received the IY parent-training to a matched control group of families (n = 690) with children in the same age-span (2-12 years, M = 3.6 years) drawn from the national registers. Propensity score matching is a means of enhancing baseline family comparability across several (socioeconomic, demographic, and health) factors between matched intervention and control families to mimic an experimental design. Multiple linear regression models were conducted to compare the average annual family income in intervention, control and background population (n = 292,966) families across a 7-year time-span from 2 years prior to the intervention to 4 years after.<br/><br/>Results: Intervention families experienced widening income disparities compared to control (from -0.1% to 4.8%, p = .000) and background population families (from 17% to 20%, p = .000), from two years before to four years after the intervention. Long-term income inequalities were not mitigated by participation in parent-training.<br/><br/>Implications: While the IY parent-training program effectively targets disruptive child behaviors, economically disadvantaged families in Denmark may require additional systemic and contextual supports to mitigate long-term economic vulnerabilities. This underscores the importance of addressing the broader family context, including family economy, as well as parent-child interactions in families with high levels of disruptive child behaviors.