Deliberative Mini-Publics and Perceived Legitimacy: The Effect of Size and Participant Type

Public participation is often used to increase the legitimacy of public decision-making. By involving citizens more directly in the public decision-making process, governments and other public actors try to increase the extent to which a particular decision-making process is considered legitimate (see King et al. 1998; Halvorsen 2003). A recent addition to the public participation toolbox is the deliberative mini-public. Defined as an institution in which a group of randomly selected citizens convenes to deliberate on public issues, the concept is usually thought to include consensus conferences, citizen assemblies and deliberative polls (see Goodin and Dryzek 2006; Ryan and Smith 2014). Yet, this definition of deliberative mini-publics hides a considerable degree of variation. While all mini-publics combine the random selection of participants with a commitment to facilitating deliberation, individual mini-publics can have radically different designs (see Smith 2009). Whereas the smallest mini-publics consist of 10-20 citizens, the largest feature up to 1000 (c.f. Caluwaerts and Reuchamps 2018). Similarly, while most mini-publics aim to select a cross-section of all citizens, some select only those citizens that are directly affected by a particular decision (c.f. Carter and Martin 2018). Although previous research has acknowledged the importance of these differences (see Bächtiger et al. 2014), there have been few attempts to study their effect on the legitimating power of deliberative mini-publics. While a growing body of studies argues that mini-publics can improve the perceived legitimacy of a public decision-making process (c.f. Dryzek and Tucker 2008; Boulianne 2018), it has generally failed to take the impact of design characteristics like size and participant type into account. As a result, it is largely unknown if and to what extent the legitimating effect of deliberative mini-publics is moderated by these characteristics. In this paper, I will attempt to answer this question by means of two survey experiments. For the first, undergraduate students (N = 141) were randomly divided into four experimental groups. Each group was presented with a brief description (a vignette) of a public decision-making process that featured a deliberative mini-public. Depending on the group, this mini-public involved either 30 or 1000 citizens, and either citizens in general or only citizens that would be directly affected. Having read the vignette, all participants were asked a series of questions to determine if and to what extent they considered the decision-making process legitimate. The second experiment mirrored this design, but was conducted using a representative sample of Dutch citizens (N = 5000). On the one hand, this study will help to develop academic work on deliberative mini-publics as a form of public participation. By studying the effects of size and participant type, it contributes to debates on both the design of participatory institutions and the drivers of perceived legitimacy. However, it will also aid practitioners who seek to improve the legitimacy of public decision-making. By studying how certain design characteristics affect the legitimating power of a deliberative mini-public, it will provide these participants with the means to tailor the design of mini-publics, thereby making them more effective.