Can either using cognitive science principles or improving teacher content knowledge boost student achievement in middle school science?

This study used a cluster randomized controlled trial to investigate the effectiveness of two approaches to increasing middle school students' science learning when using an inquiry‐based science curriculum. Eighty‐nine schools, with 253 teachers and 20,591 students, were randomly assigned into one of three conditions: (a) a treatment condition in which the textbook curriculum was modified based on three principles of cognitive science coupled with teacher professional development (PD), (b) a second treatment condition in which teachers received PD designed to improve their knowledge of the science content, and (c) a business‐as‐usual control group. The cognitive science treatment had a small but statistically significant positive effect on content learning, with a stronger impact on students of higher prior achievement. Compared to business‐as‐usual, the intervention to increase teacher content knowledge had no impact. [ABSTRACT FROM AUTHOR]