Deliberative, Representative, or Both? How Institutionalising Minipublics in Policymaking Shapes Political Attitudes

Democratic innovations, such as deliberative minipublics, bring together a broadly representative group of citizens to reason on a political issue through facilitated deliberation and access to expert advice (Smith and Setälä, 2018). In recent years, they have been increasingly used to complement existing policymaking processes (OECD, 2020). Advocates argue minipublics can help address political discontent and improve decision-making (Dryzek et al., 2019). At the same time, their growing institutionalisation raises questions about how they can be used effectively within constitutional democracies (Courant, 2022). One important way in which minipublics can strengthen democratic resilience is by influencing the political attitudes of the wider public (van der Does and Jacquet, 2023). While existing studies show that minipublics can improve perceived legitimacy and shape policy preferences beyond their participants, we know less about why and under what conditions these effects occur (Goldberg, 2023). To address these gaps, this paper presents findings from a nationally representative factorial survey experiment fielded in the UK. Existing research has identified two broad mechanisms by which minipublics may affect the wider public. First, they can improve legitimacy perceptions by signalling a fair, inclusive process that gives ordinary citizens greater voice (Werner and Marien, 2022). Second, they can influence policy preferences by presenting a more informed and considered version of public opinion as an alternative political cue (Warren and Gastil, 2015). However, these explanations often bundle several theoretically relevant features of minipublics together, making it difficult to isolate what drives their effects. The paper refines these mechanisms by proposing a distinction between two core features of minipublics: deliberation and representation. Deliberation refers to participants’ engagement with balanced information and inclusive discussion, while representation refers to the selection of participants to reflect key demographics and attitudes (Curato et al., 2021). Both features plausibly affect legitimacy and policy preferences, but through distinct mechanisms. For example, minipublics may enhance perceived legitimacy through representative signals that suggest a fairer process, or through deliberative signals that indicate a more epistemically valid decision. This study tests these expectations using a factorial survey experiment that is designed to elicit policy preferences and legitimacy perceptions. Respondents are randomly assigned to hypothetical scenarios that vary systematically across several dimensions: the institutional link with formal decision-making (parliamentary or referendum-based, acceptance or rejection of recommendations), the source of policy advice (citizens’ assemblies, expert advice, polling, public consultation, or town hall meetings), and the policy issue. This design advances our understanding in three important ways. First, it helps contextualise existing findings by comparing the effects of minipublics upon the wider public with advisory bodies commonly used in constitutional democracies. Second, it helps explain mixed findings by varying institutional and policy-specific conditions. Third, it expands existing theories by testing whether the effects of minipublics are driven by their perceived deliberativeness, representativeness, or the combination of both. More broadly, the paper contributes to contemporary debates about democratic renewal and suggests ways in which deliberative innovations may be designed to address specific deficits when institutionalised in traditional policymaking.