Democratizing expertise: lived experience as evidence in citizens’ assemblies

Democratic policymaking is said to require the wisdom of crowds. Yet complex issues require expert input. Citizens’ assemblies, which bring together randomly selected citizens and professional experts, appear to reconcile these demands. However, professional experts often exert strong influence on assembly members, risking the marginalization of lay and local knowledge. This paper evaluates an intervention in the Southampton Citizens’ Climate Assembly that introduced ‘citizen witnesses’ – individuals sharing lived experience relevant to the topic with the assembly members – to foster a more inclusive and democratic knowledge-building process. Analyzing survey data, field notes, and interviews with assembly members, we find that citizen witnesses complemented professional expertise and influenced the assembly not only by providing additional information but also by reshaping how assembly members understood the issue under deliberation. Their testimonies prompted reflection on blind spots, privilege and unequal exposure to policy consequences, broadening assembly members’ understanding of the policy problem. They also encouraged members to draw more confidently on their own experiences during deliberation, reinforcing the legitimacy of lived experience as a source of knowledge in collective decision-making. These findings suggest that citizen witnesses can help democratize expertise within citizens’ assemblies by elevating the standing of lay knowledge alongside professional expertise.