The Long-Term Effects of Preschool Interventions: How Access, Timing, and Quality Impact Development

• In Event: The Long-Term Effects of Preschool Interventions

Abstract

This longitudinal study investigates how classroom quality from pre-kindergarten through fourth grade influences children’s academic and social-emotional development. Drawing on the “pre-K fadeout” hypothesis, we ask: (1) Does high-quality pre-K predict sustained gains in language, literacy, and behavior? (2) Do high-quality elementary classrooms reinforce or extend these gains? We hypothesize that children exposed to both high-quality pre-K and sustained high-quality elementary classrooms will show the strongest developmental outcomes, particularly in vocabulary and behavior, highlighting the cumulative value of consistent educational quality. 

We followed 390 children enrolled in Georgia’s Pre-K in 2013–14 through fourth grade. The sample was racially and economically diverse: 36% Black, 15% Hispanic/Latine, 47% White; 55% low-income. Classroom quality was assessed annually using the Classroom Assessment Scoring System (CLASS Pre-K, Pianta et al., 2008; CLASS K-3, Pianta et al., 2008, & CLASS Upper Elementary, Pianta et al., 2012), with high-quality defined by thresholds for Emotional Support (≥5), Classroom Organization (≥5), and Instructional Support (≥2.5). The proportion of observed classrooms that met this threshold in all three domains was highest during the pre-K year (53.59%) and lower Kindergarten-4th grade (24.62%- 35.13%). We examined three predictors: (1) high-quality pre-K attendance, (2) proportion of high-quality classrooms from kindergarten through fourth grade, and (3) their interaction. Outcomes included language, literacy, math (Woodcock-Johnson III W-scores; Woodcock et al., 2001), and social-emotional development (SSIS standard scores; Gresham et al., 2008). Multi-level random intercept growth models centered at the end of pre-K allowed us to assess the impact of high-quality pre-K while controlling for baseline scores and varying exposure to later classroom quality. Quadratic models were used for academic outcomes; linear models for social-emotional outcomes. Robustness checks tested sensitivity to quality thresholds versus continuous measures.  

High-quality pre-K predicted stronger early literacy outcomes (letter-word identification, decoding, vocabulary), though literacy effects narrowed over time. Vocabulary gains persisted. A higher proportion of high-quality classrooms in K–4 predicted stronger vocabulary and social skills growth and fewer behavior problems. Children who experienced both high-quality pre-K and sustained high-quality elementary classrooms showed the greatest benefits, especially in vocabulary and behavior. These findings suggest additive effects of sustained quality across early education years.  

This study highlights the need for sustained high-quality classroom experiences beyond pre-K. While high-quality pre-K lays a strong foundation, long-term benefits rely on continued exposure to enriching environments through elementary school. To maximize early investments, systemic approaches must replace isolated interventions, especially for underserved communities. Strengthening classroom quality across K–4 supports lasting academic and behavioral gains. Using five years of longitudinal classroom and child data, the study examines additive effects of sustained quality and how early gains persist or fade depending on later environments. It contributes to the “fadeout” debate by emphasizing the importance of continuity in classroom experiences.

Author

• Sandra Soliday Hong, University of North Carolina, Chapel Hill
  Presenting Author