A four-arm randomised controlled trial examining PD effects on student achievement.
PD intervention was pedagogy-focused Quality Teaching Rounds (QTR).
QTR has significant impact on students’ mathematics achievement.
PLCs undertaking peer observation insufficient for growth in achievement.
QTR is a powerful form of PD with significant potential for wider impact.
Improving student achievement through professional development (PD) is both highly sought-after and elusive. This four-arm randomised controlled trial evaluated effects of Quality Teaching Rounds (QTR), a pedagogy-focused form of PD, on mathematics, reading, and science outcomes for elementary students (n = 5478). Outcomes at baseline and 8-month follow-up were compared for QTR, QTR trainer-led, peer-observation, and wait-list control groups. Students in the QTR group made 25% more progress in mathematics than the control group (g = 0.12, 95% CI: 0.07–0.17). This result supports QTR as a form of PD with significant potential for wider impact.