{ "background": "The quality of science education in many African contexts is constrained by limited opportunities for teachers to develop sophisticated pedagogical content knowledge (PCK). In chemistry, where abstract concepts dominate, this gap is particularly acute. Current in-service teacher development programmes often lack structured, collaborative, and subject-specific mechanisms for PCK growth.", "purpose and objectives": "This policy analysis examines the efficacy of a structured peer observation protocol as a mechanism for enhancing the pedagogical content knowledge of secondary school chemistry teachers. It aims to evaluate the protocol's design, implementation challenges, and its specific impact on teachers' understanding of how to represent chemical concepts effectively.", "methodology": "The analysis synthesises evidence from a mixed-methods case study involving chemistry teachers in Ibadan. Data were derived from pre- and post-observation interviews, lesson artefacts, reflective journals, and focus group discussions to triangulate shifts in PCK components. Policy documents on teacher professional development were concurrently analysed.", "findings": "Implementation of the structured protocol led to measurable improvements in teachers' PCK, particularly in their knowledge of instructional strategies for challenging topics. A key theme was the move from teacher-centred didacticism to the use of more interactive analogies and models. For instance, over three-quarters of participants demonstrably refined their approach to teaching reaction kinetics following the observation cycle.", "conclusion": "Structured peer observation, when focused on subject-specific pedagogical dilemmas, is a viable and impactful policy tool for fostering PCK development. It provides a sustainable, contextually relevant alternative to top-down training workshops.", "recommendations": "Education policymakers should integrate structured, subject-specific peer observation protocols into national teacher development frameworks. School leaders must be supported to create schedules and cultures that enable collaborative inquiry. The chemistry-specific protocol analysed here should be adapted and piloted for other STEM disciplines.", "key words": "pedagogical content knowledge, teacher professional development, peer observation, chemistry education, policy analysis, Nigeria", "contribution statement": "This paper provides a novel
Okonkwo et al. (Tue,) studied this question.