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…

Problem/Purpose: Young children with developmental speech and/or language impairment (DSLI) often fail to develop important oral language and early literacy skills that are foundational for subsequent schooling and reading success. The purpose of this investigation was to examine the efficacy of the TELL curriculum and associated evidence-based…

We investigated whether individual differences in overall receptive vocabulary knowledge measured at the beginning of the year moderated the effects of a kindergarten vocabulary intervention that supplemented classroom vocabulary instruction. We also examined whether moderation would offset the benefits of providing Tier-2 vocabulary intervention…

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…