Seattle Preschool Program RCT

Summary

Seattle's Preschool Program produced one of the few lottery-based RCTs of a universal municipal pre-K program in the United States. The lottery-based design — created by program oversubscription, not by deliberate randomization — provided a credible control group. Effects of roughly one-third of a standard deviation in school readiness are consistent with other high-quality early childhood programs and substantially larger than typical short-term education interventions. The finding that effects were largest for dual-language learners and the lowest-income children supports the targeting argument: universal programs can deliver their largest benefits to the most disadvantaged participants when quality is maintained.

Research question

"Does a universal publicly funded preschool program improve kindergarten readiness for low-income children?"

Methodology

Result

Positive

School readiness: +0.32 SD; language development: +0.28 SD; social-emotional skills: +0.19 SD; effects largest for dual-language learners and lower-income families

Evidence strength

Strong

Randomized controlled trial with large sample.

Replication status

Partially replicated