Measuring the quality of teacher professional development

Teacher professional development (TPD) is widely considered a key lever for improvinginstructional quality and student learning. Yet, evidence reveals significant variation inits eUectiveness. One explanation lies in diUerences in TPD quality, a multidimensionalconstruct that remains conceptually fragmented and diUicult to measuresystematically.This chapter defines TPD as structured, formally organized learning opportunities andconceptualizes its quality as a multidimensional construct encompassing input,process, and outcome dimensions. Particular emphasis is placed on process quality,captured through four overarching dimensions: clarity and structure, practicalrelevance, cognitive activation, and collaboration.We review methodological approaches to assessing TPD quality and group them intothree strands: explorative approaches that use ad-hoc indicators without systematicvalidation, standardized and validated instruments that oUer more robust measurement(e.g., TPD Monitor, IMPRESS), and indirect approaches that measure quality throughsecondary or large-scale data (e.g., ITTSI). Each approach contributes valuable insightsbut also has clear limitations, with current evidence remaining fragmented acrosscontexts and methods.Several challenges are highlighted, including the lack of conceptual clarity, limitedpsychometric validation, insuUicient knowledge of convergent validity across diUerentdata sources, and practical barriers to large-scale monitoring. Open questions remainabout threshold levels of quality, the diUerential eUects of specific quality dimensions,and the validity of assessments provided by diUerent actors.The chapter concludes that valid, reliable, and scalable measurement tools areessential not only for research but also for improving professional developmentsystems.