Learning from practice: Expanding the OECD’s impact evaluation criteria based on experiences of subnational climate assemblies in France, Spain and Portugal

Climate Assemblies (CAs) aim to incorporate citizens’ perspectives into public policy. To evaluate their policy impact, researchers often rely on the OECD’s evaluation criteria, which are designed for a broad range of deliberative processes. However, recent CAs developments—particularly at the subnational level—have introduced innovative practices that are not fully captured by these existing frameworks. In response to ongoing academic debates on CAs and its impact measurement, this study draws on practical experiences and discourses to refine and expand the OECD’s policy impact criteria. Based on semi-structured, in-depth interviews with 14 key informants involved in 8 subnational CAs in France, Spain, and Portugal, our aim is to adapt the policy impact criteria by integrating academic debates and empirical insights from subnational contexts. Traditionally, policy impact evaluation has been treated as a separate dimension, disconnected from the design and implementation phases. However, our thematic analysis reveals that a holistic evaluation of the entire CA process is necessary to accurately assess its impact. Thus, we argue that key factors—such as the alignment of mandates with existing public policies, the inclusion and roles of various social actors throughout the process, and internal governance structures—must be considered in future evaluation frameworks. Ultimately, we offer new considerations and adaptations that enhance the assessment of policy impact for subnational CAs. • CA policy impact evaluation is inseparable from its design and implementation phases. • The alignment of CA’s mandates with policy plans has to be evaluated. • Examining how relevant authorities and wider public are included in the CA’s process. • Subnational level particularities have to be addressed in CAs’ evaluation.