Justice demands that no one should do more ruling than being ruled, but that all should have their turn – Aristotle
This age-old quote demonstrates the aim of deliberative mini-publics (DMPs). In a DMP, a representative group of citizens comes together to discuss public issues and to create policy recommendations. Such initiatives aim to make the democratic system more participatory and rebuild political trust.
This research aimed to examine how the size of a DMP affects citizens’ perceptions of its legitimacy. While larger groups may enhance representativeness, they can hinder deliberation quality, process efficiency, and outcome efficacy. This study examined how citizens balance these dimensions of legitimacy and which size is seen as optimal.
We conducted two surveys (study 1: n = 516 UK citizens; study 2: n = 527 UK citizens), where participants read about the concept of a DMP and subsequently evaluated eight different group sizes on the four dimensions of legitimacy. Additionally, for each group size, participants filled in an overall evaluation item. Furthermore, participants had to decide how many citizens they thought a DMP should ideally consist of. Lastly, the participants had to indicate their general support for both DMPs and referendums.
The findings showed that the majority of participants (75%) made trade-offs between achieving representativeness and ensuring deliberation, efficiency, and efficacy. They rated the 100-citizen DMP as the most optimal, showing that most citizens intuitively balance the various legitimacy dimensions to come to a feasible size preference.
However, a substantial minority (25%) valued the involvement of large groups of citizens above other considerations. These participants believed DMPs should consist of more than 1,000 citizens. This group also expressed stronger support for referendums than for DMPs. Hence, for a subset of citizens, representativeness is the most important aspect of participatory democracy.
What Do We Learn From This?
As the majority perceived a 100-citizen DMP as most optimal in terms of balancing representativeness, deliberation, efficiency, and efficacy, this could be seen as a practical guideline for organizers of DMPs. However, we want to emphasize that 100 citizens should not be seen as a strict rule, as different contexts may require different approaches. Nevertheless, in any context, we believe it is important to reflect on how participatory initiatives will be perceived by citizens. DMPs may not always match what citizens expect in terms of size, and addressing this concern through clear communication about achieving a balance between ideals and feasibility may help garner support.
Furthermore, this research underscores the importance of using hybrid forms of democratic participation. Some formats promote debate while others ensure representation. By combining different models, the strengths of one can mitigate the weaknesses of the other. For instance, in Ireland, there have been several cases where a DMP formulated propositions that were subsequently approved by the population through a referendum. Such a two-stage format may help in meeting the expectations of all citizens and improve the trade-off between the various dimensions of legitimacy.
Read the original article in Policy Studies Journal:
Waterschoot, Milena, Tessa Haesevoets, and Arne Roets. 2026. “The Optimal Group Size of Deliberative Mini-Publics: A Divide in Perceptions”. Policy Studies Journal 54(1): 1-16. https://doi.org/10.1111/psj.12592.
About the Article’s Author(s)

Milena Waterschoot is a PhD candidate at the Department of Developmental, Personality and Social Psychology of Ghent University. Her research revolves around deliberative democracy and violent extremism.

Tessa Haesevoets is a senior researcher at the Department of Public Governance and Management of Ghent University. Her research interests include trust repair, participation, expert-based democracy, artificial intelligence, and public administration.

Arne Roets is an associate professor at the Department of Developmental, Personality and Social Psychology of Ghent University. His research focuses on judgment and decision-making, moral and political psychology, participation, and intergroup relations.






