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Peace, Justice and Strong Institutions- For development
- Brief created: 2025
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Size doesn’t matter? For the legitimacy of deliberative mini-publics, it does.
Brief about:
Journal Article (2025)
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Other researchers:
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.
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.
Key findings
- 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 meansCitizens 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 meansMost 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 meansFor 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.
A 100-citizen DMP is perceived by the majority as the most optimal in terms of balancing representativeness, deliberation, efficiency, and efficacy.
However, we want to emphasize that 100 citizens should not be seen as a strict rule: DMPs vary widely, and different contexts may require different approaches, in addition to considering practical feasibility. Nevertheless, in any context, we believe it is important to reflect on how deliberative initiatives will be perceived by citizens. Moreover, understanding citizens' expectations regarding the size of DMPs may also allow for more effective communication. DMPs may not always match what citizens expect in terms of size, and addressing this concern in a clear communication about achieving a balance between ideals and feasibility may help garner support.
- Combine DMPs with broader forms of citizen participation.
Hybrid forms of democratic participation may help in meeting the expectations of all citizens. Even more, such hybrid forms can help improve the trade-off between the various dimensions of legitimacy: some formats promote debate, 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. This shows that it is possible to combine different forms of participatory democracy.
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Size doesn’t matter? For the legitimacy of deliberative mini-publics, it does.
Cite this brief: Waterschoot, Milena. 'Size doesn’t matter? For the legitimacy of deliberative mini-publics, it does.'. Acume. https://www.acume.org/r/size-doesnt-matter-for-the-legitimacy-of-deliberative-mini-publics-it-does/
Brief created by: Milena Waterschoot | Year brief made: 2025
Original research:
- Haesevoets, T., Waterschoot, M., & Roets, A., ‘The optimal group size of deliberative mini-publics: A divide in perceptions’ Policy Studies Journal https://doi.org/10.1111/psj.12592. –
Research brief:
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.
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.
Findings:
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.
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.
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.
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.
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.
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.
For a subset of the population, representativeness is the most important aspect of participatory democracy.
Advice:
A group of 100 citizens as a practical guideline for organizers of DMPs.
- However, we want to emphasize that 100 citizens should not be seen as a strict rule: DMPs vary widely, and different contexts may require different approaches, in addition to considering practical feasibility. Nevertheless, in any context, we believe it is important to reflect on how deliberative initiatives will be perceived by citizens. Moreover, understanding citizens’ expectations regarding the size of DMPs may also allow for more effective communication. DMPs may not always match what citizens expect in terms of size, and addressing this concern in a clear communication about achieving a balance between ideals and feasibility may help garner support.
Combine DMPs with broader forms of citizen participation.
- For instance, in Ireland, there have been several cases where a DMP formulated propositions that were subsequently approved by the population through a referendum. This shows that it is possible to combine different forms of participatory democracy.