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Summaries of RCT Grants

Comparing full-day and half-day preschool: Long-term follow-up of an RCT

This study extends the follow-up of a randomized controlled trial (RCT), comparing full-day preschool to half-day preschool, and will provide policymakers and parents the most rigorous evidence to-date on the relative effectiveness of full-day versus half-day preschool in preparing children for elementary school.

Grant Recipient: University of Colorado-Boulder

Term: 2018 –2024

Principal Investigator: Allison Atteberry, Ph.D., University of Colorado-Boulder

Funding: $489,628

Summary: This study extends the follow-up of a randomized controlled trial (RCT), comparing full-day preschool to half-day preschool, and will provide policymakers and parents the most rigorous evidence to-date on the relative effectiveness of full-day versus half-day preschool in preparing children for elementary school.

The study is taking place in Westminster Public Schools (WPS), a school district in suburban Denver. Since full-day preschool slots are limited in WPS, families interested in full-day preschool are randomly assigned through a lottery each fall to either be offered (i) a full-day preschool slot (the treatment group for this study) or (ii) a half-day preschool slot (the control group for this study). Students in full-day preschool spend 30 hours per week in their classrooms, whereas students in half-day preschool receive 12 hours of classroom time per week.

The study’s sample includes families who participated in the lotteries for the 2016-2017, 2017-2018, and 2018-2019 school years. Across all three lotteries, the researchers anticipate a total sample of approximately 800 predominantly low-income, minority students.

For the students who participated in the 2016-2017 lottery, the study has already found that full-day preschool produced promising impacts on measures of early literacy in the fall of kindergarten (the average treatment group student scored higher than 64% of control group students, an effect size of 0.34 standard deviations). The study will measure sample students’ reading and math achievement (i) in kindergarten, using the district’s standardized assessment and (ii) in third grade, using Colorado’s state test.

The study’s pre-specified analysis plan is linked here.

Grants

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