Abstract
<p>This meta-analysis examined the impact of professional development (PD) design features on teacher outcomes by comparing PD interventions to active control conditions with planned variations in format, duration, content, and delivery. The study aimed to move beyond business-as-usual (BAU) comparisons to identify which PD features most effectively support teacher learning. Secondary data analyses of the Teacher Outcomes and Professional Development (TOPD) database was conducted. The TOPD database was created using comprehensive search methods of published and unpublished research between 1986 and 2023 and includes 112 randomized controlled and quasi-experimental design studies where PD was the primary intervention for preschool through 12th grade teachers (Authors, 2025a). Meta-analysis and subgroup analyses were conducted to examine the impact of variations in PD features (i.e., format, duration, content, delivery), standardized measures, and research design. PD with active control conditions yielded a significant overall effect on teacher outcomes. Studies using BAU comparisons reported larger effect sizes than those with active control conditions. Researcher-created measures produced significantly larger effects than standardized assessments. Among active control studies, variations in format and duration were most commonly tested and yielded the largest effects. Increasing the number of PD variations did not consistently enhance effectiveness. Findings highlight the limitations of BAU comparisons and highlight the importance of rigorous, feature-specific PD research. Future research should prioritize active control comparisons and intentional variation in PD features to better inform practice and policy.</p>