The impact of school exclusion on mental health and behavioural outcomes: A counterfactual analysis using a large UK-representative study

Research suggests that experiencing school exclusion is associated with poorer psychosocial outcomes for children; however, this association is vulnerable to confounding. Using a large UK-based longitudinal study, the Millennium Cohort Study (n=9551; 129 treated and 129 matched controls), and leveraging a wide range of matching variables we used counterfactual analyses to examine the effects of school exclusion at age 11 on emotional problems, conduct problems, ADHD symptoms, peer problems and prosociality at age 14, accounting for confounding. We found that young people who experienced school exclusion had significantly worse scores at age 14 on all of these outcomes. The use of propensity score matching (including matching on prior behavioural problems) strengthens confidence in the idea that the effects are causal. Results point to the need for policies oriented towards reducing school exclusions and ensuring mitigating measures are in place to minimise its impact on those who experience it.