Size doesn’t matter? For the legitimacy of deliberative mini-publics, it does.
- For development
- Summary created: 2025
Investigates the optimal group size for deliberative mini-publics (DMPs) as perceived by citizens, focusing on four dimensions of legitimacy: representativeness, deliberation quality, efficiency, and efficacy.
This summary, including its recommendations and ideas, was created by Milena Waterschoot and is based on original research. The original research itself was conducted in collaboration with the following researchers.
Deliberative mini-publics (DMPs) bring together a “representative” group of citizens to deliberate on public issues and to create policy recommendations. These initiatives aim to make the democratic system more participatory and rebuild political trust.
This research addressed a gap in understanding 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 most optimal for DMPs.
Insights
The majority of participants (~75%) stated that DMPs should consist of less than 1000 participants. However, a substantial minority (~25%) stated that DMPs should consist of more than 1000 participants.
Evidence
In two surveys (study 1: n = 516 UK citizens; study 2: n = 527 UK citizens), participants were asked through an open response format how many citizens they thought a DMP should ideally consist of.
What it means
Citizens differ strongly in what they consider the optimal size for DMPs
The majority of participants made trade-offs between achieving representativeness and ensuring deliberation, efficiency, and efficacy. In terms of a legitimacy balance, the group of 100 citizens was the most favorable.
Evidence
In two surveys (study 1: n = 516 UK citizens; study 2: n = 527 UK citizens), 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.
What it means
Most participants seem to intuitively balance the various dimensions to come to a feasible size preference.
A substantial minority valued the involvement of large groups of citizens above other considerations. These participants also expressed a stronger support for referendums than DMPs.
Evidence
In two surveys (study 1: n = 516 UK citizens; study 2: n = 527 UK citizens), 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. Lastly, at the end, the participants had to indicate their general support for both referendums and DMPS.
What it means
For a subset of the population, representativeness is the most important aspect of participatory democracy.
Proposed action
A group of 100 citizens as a practical guideline for organizers of DMPs.
Combine DMPs with broader forms of citizen participation.
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