Enhancing students’ mathematics achievement through teacher professional development on peer- and self-assessment: A randomized controlled trial

This cluster-randomized trial examined whether a content-specific professional development program on formative peer- and self-assessment supports primary students' calculation strategy repertoire. Therefore, N = 96 Grade 4–5 teachers with their classes ( N = 1525 students) were assigned to peer-assessment, self-assessment, or waitlist control conditions. The researcher-developed professional development program targeted teacher orchestration of peer- and self-assessment on multiplication and division strategies, grounded in formative assessment theory and mathematics-specific frameworks (e.g., Developing Mathematical Thinking). The primary outcome was students’ breadth of distinct correct strategies per item. Both intervention groups showed statistically significant, educationally meaningful gains ( d = 0.36 posttest; d = 0.29 follow-up) compared with controls, with similar results for peer- and self-assessment. Results suggest that a concise, content-focused professional development can help teachers implement formative peer- and self-assessment in ways associated with a broader strategy repertoire in multiplication and division.