Measuring and Reporting the Impact of Participation Processes on Collective Decisions in Policymaking: A Practical Guide for Delineation, Conceptualization, and Operationalization

Participation processes worldwide seek to influence collective decision-making in the face of declining trust in elites and political institutions grappling with the complex policy issues such as climate change and migration. Democratic innovations, notably mini-publics, are touted as potential catalysts for improved public policy-making, for instance, by empowering hesitant policymakers, breaking political deadlock, or challenging existing agendas. However, mini-publics' impact on public policy decisions is often questioned. Despite the critical importance of understanding the policy impacts of participation processes, robust knowledge on this subject remains limited, primarily due to conceptual and methodological challenges in measuring causal impact. Many researchers hesitate to undertake such studies, and existing analyses often lack robustness, relying only on the congruence between process outputs and subsequent policy documents. Comparing and interpreting findings across studies are further hindered by variations in reporting and occasional lack of transparency or clarity. This paper serves as a practical guide on how to measure and report the impact of participation processes on collective decisions. It systematically navigates through essential steps, encompassing concept delineation, concept definition, operationalizing measurement, data collection and analysis, and addressing uncertainties. Key questions addressed include the identification of different impact types, the criteria for sufficient evidence of causal impact, the definition of the political arena for collective decisions, identification of relevant data sources, and determination of the appropriate unit of analysis. Each step is critically discussed, presenting alternative choices. The practical guide is then applied to analyze the impacts of 43 recommendations made by a citizens’ assembly on climate change held in Berlin in 2022. Findings reveal that the assembly did impact collective decisions made by the Berlin government. While government reported uptake of 90% of the recommendations, our analysis indicates that less than 25% had a causal impact on government decisions. Despite relatively low proportions, the study provides supportive evidence of enriching, fortifying, innovating, and political impact types, offering valuable theoretical insights into the capacity of mini-publics to enhance public policymaking.