This study is a randomized control trial of full- versus half-day prekindergarten (pre-K) in a school district near Denver, Colorado. Four-year-old children were randomly assigned an offer of half-day (4 days/week) or full-day (5 days/week) pre-K that increased class time by 600 hours. The full-day pre-K offer produced substantial, positive…

This study evaluated the effects of a cross-age peer learning program targeting vocabulary and comprehension in kindergarten and fourth-grade classrooms with substantial proportions of English Learners (ELs). The study followed a quasi-experimental design with 12 classrooms (6 kindergarten and 6 fourth grade) in the intervention group and 12…

A two-cohort cluster randomized trial was conducted to estimate effects of small-group supplemental vocabulary instruction for at-risk kindergarten English learners (ELs). "Connections" students received explicit instruction in high-frequency decodable root words, and interactive book reading (IBR) students were taught the same words in…