State Prekindergarten Effects on Early Learning at Kindergarten Entry: An Analysis of Eight State Programs

W. Steven Barnett, Ph.D.

State-funded prekindergarten programs are increasingly common across the country. This study published online in AERA Open estimated the effects of eight state-funded pre-K programs in Arkansas, California, Michigan, New Jersey, New Mexico, Oklahoma, South Carolina and West Virginia on children’s learning using a regression discontinuity design.

These programs vary with respect in the population served, program design, and context.

Weighted average effect sizes from instrumental variables analyses across these states are 0.24 for language (vocabulary), 0.44 for math, and 1.10 for emergent literacy.

Differences in effect sizes by domain suggest that pre-K programs should attend more to enhancing learning beyond simple literacy skills. State pre-K programs appear to differ in their effects. The report offers recommendations for more rigorous, regular evaluation.

“We studied a diverse array of public preschool programs and they all produced large short-term effects on the simplest, easiest to acquire skills,” the report states. “But on average programs had much more modest effects on language acquisition; in some states estimated language effects were near zero.”

The pattern raises concerns, the report notes, because language development in the preschool years is important and large boosts to deep learning in language and math are more likely to lead to long-term gains in achievement and school success.

“Our study adds to the evidence that public pre-K can improve learning and development for both disadvantaged and general populations, at least in the short term,” the report states. “It also raises concerns about the need to improve quality. State pre-K program effectiveness cannot simply be assumed but should be measured regularly with a goal of continuous improvement.”

“States should not rely on assessment of narrow literacy skills alone…,” the report states. “Monitoring and evaluation of pre-K program effectiveness should…include language, mathematics, and other measures predictive of long-term achievement and school success.”

NIEER co-authors include W. Steven Barnett, Kwanghee Jung, Allison Friedman-Krauss, Ellen C. Frede, and Milagros Nores.