The Effects of Universal Pre-K on Cognitive Development.

TLDR

The study used a regression‑discontinuity design based on a strict birthday eligibility rule, comparing 1,567 pre‑K children who had just completed pre‑K with 1,461 kindergarteners who were just beginning pre‑K, and estimated effects on Woodcock‑Johnson Achievement test scores. The program raised Woodcock‑Johnson scores by 3.00 points in Letter‑Word Identification, 1.86 in Spelling, and 1.94 in Applied Problems, benefiting Hispanic, Black, White, and Native American children across income levels and improving overall school readiness.

Abstract

In this study of Oklahoma's universal pre-K program, the authors relied on a strict birthday eligibility criterion to compare "young" kindergarten children who just completed pre-K to "old" pre-K children just beginning pre-K. This regression-discontinuity design reduces the threat of selection bias. Their sample consisted of 1,567 pre-K children and 1,461 kindergarten children who had just completed pre-K. The authors estimated the impact of the pre-K treatment on Woodcock-Johnson Achievement test scores. The authors found test impacts of 3.00 points (0.79 of the standard deviation for the control group) for the Letter-Word Identification score, 1.86 points (0.64 of the standard deviation of the control group) for the Spelling score, and 1.94 points (0.38 of the standard deviation of the control group) for the Applied Problems score. Hispanic, Black, White, and Native American children all benefit from the program, as do children in diverse income brackets, as measured by school lunch eligibility status. The authors conclude that Oklahoma's universal pre-K program has succeeded in enhancing the school readiness of a diverse group of children.