The Breadth of Impacts from the Abecedarian Project Early Intervention on Cognitive Skills

Early life interventions impacting cognitive abilities are most often followed by post-treatment fadeout. Some have hypothesized that persistence is unlikely when gains are specific to trained skills, or more specifically, distinguishable from impacts on general cognitive ability (classically modeled as a hierarchical factor, so-called psychometric g). Using measurement invariance testing and multiple indicators multiple causes models, we investigated impacts on IQ subtests from the Abecedarian early childhood intervention (n = 107). We found that 1) observed impacts on IQ scores from age 5 to age 21 were consistent with persistent positive effects on g; 2) subtest-specific variance that was differentiable from changes on g did fade. Together, these findings indicated that Abecedarian early impact persisted across a range of cognitive skills, providing some evidence for the hypothesis that breadth and persistence of impacts from educational interventions are related.