Boston Public Pre-K Program
Harvard Graduate School of Education (Weiland, Yoshikawa) · Boston, Massachusetts, USA · 2009
Summary
The Boston pre-K evaluation stands out in the early childhood literature for producing some of the largest school readiness effects ever documented in a US public program. The key design features — structured curriculum, intensive teacher coaching, and full-day programming — distinguished Boston's program from lower-intensity alternatives evaluated in Head Start and state pre-K studies. The executive function gains (0.45 SD) were particularly notable because executive function (the ability to regulate attention, inhibit impulses, and shift between tasks) predicts later academic success more strongly than early academic skills alone. The study also contributed to an important methodological debate: regression discontinuity designs around age cutoffs can recover causal estimates of pre-K effects without random assignment, allowing natural experiments where lottery-based RCTs are politically or logistically infeasible.
Research question
"Does a high-quality urban public pre-K program with a structured curriculum and coaching produce gains in school readiness, and do those gains persist into kindergarten?"
Methodology
Intervention
Boston Public Schools expanded its pre-K program using a structured, evidence-based curriculum (Opening the World of Learning and Tools of the Mind in different cohorts) with intensive teacher coaching. The program operated in public schools with a full school day and focused on language development, literacy, and executive function.
Assignment
Regression discontinuity based on the age enrollment cutoff; children born just before vs. just after the enrollment cutoff were compared; fuzzy RD analysis accounting for non-compliance
Sample size
Approximately 2,018 children in the 2008–2009 cohort; multi-year study
Primary outcome
Language, literacy, mathematics, and executive function at kindergarten entry
Effect estimate
Language composite: +0.32 SD; mathematics: +0.33 SD; executive function: +0.45 SD — among the largest pre-K effects documented in the US literature; gains more than doubled those found in typical Head Start evaluations
Decision
Results contributed to evidence base supporting expansion of public pre-K; Boston model has been studied as an exemplar of high-quality implementation with structured curriculum and coaching; subsequent studies on Boston pre-K found that gains in executive function partially persisted into third grade, unusual given typical fadeout of pre-K effects
Result
Positive
Language composite: +0.32 SD; mathematics: +0.33 SD; executive function: +0.45 SD — among the largest pre-K effects documented in the US literature; gains more than doubled those found in typical Head Start evaluations
Evidence strength
Moderate
Quasi-experimental design with replication support.
Replication status
Replicated
Institution
Harvard Graduate School of Education (Weiland, Yoshikawa)
Location
Boston, Massachusetts, USA
Year
2009
Policy area
Early Childhood
Mechanism
Human capital