We use data from a randomized controlled trial of a middle school science intervention to explore the causal mechanisms by which the intervention produced previously documented gains in student achievement. Our study finds that implementation fidelity, operationalized as a measure of the frequency of implementation of the cognitive science…

The authors evaluated the effects of P-SELL, a science curricular and professional development intervention for fifth-grade students with a focus on English language learners (ELLs). Using a randomized controlled trial design with 33 treatment and 33 control schools across three school districts in one state, we found significant and meaningfully…