The Effects of Sub-Municipal Amalgamations on Turnout: Testing the Rational Voter Hypothesis

The 2013 territorial reform of sub-municipal units (SMUs) in Portugal presents an interesting opportunity to understand the effect of amalgamations on democratic outcomes. Following the experience of several Western European countries, Japan, and Australia, the Portuguese amalgamation reform was triggered by economic motivations, seeking to reduce the level of public expenditures. The amalgamation process was implemented in a compulsory manner, reducing the number of SMUs and increasing their size in order to boost efficiency, seize economies of scale, and reduce the cost of service delivery. Much less relevance was given to the potential political impacts of territorial consolidations. Populations had little influence in deciding which criteria should be used and what jurisdictions should be merged. The aim of this research is to assess the impacts of this territorial reform on political participation measured as voter turnout in SMU elections. According to the “rational voter” model (Downs 1957), the expected investment benefit of voting increases with the probability of affecting the election result, which, in turn, is influenced by the size of the population: the smaller the population, the higher the probability of casting the decisive vote (Geys 2006; Riker and Ordeshook 1968). In other words, the smaller the population of the jurisdiction, the higher the voter turnout is likely to be since few votes can make a difference and voters feel they can influence the outcome of the election (Wood 2002). We test two hypotheses derived from the rational model in the context of the amalgamation of SMUs: 1) Mergers resulting in larger size SMUs produce lower turnout rates in amalgamated SMUs; and 2) The turnout gap between amalgamated and non-amalgamated SMUs tends to increase overtime. We employ data from three election cycles (2009, 2013 and 2017) for all sub-municipal governments in Portugal and use a differences-in-differences (DiD) estimator and panel data with fixed effects to promote a dynamic comparison of turnout levels in amalgamated jurisdictions vis-à-vis the ones that did not amalgamate as a result of the process of territorial reform. Preliminary results indicate that turnout levels have decreased overall in the first election cycle after amalgamation (2013), but more so in amalgamated SMUs than in non-amalgamated SMUs. In the second election cycle after amalgamation (2017), turnout increased for all SMUs as a group, but significantly more in non-amalgamated SMUs than in amalgamated ones. These results contribute to the literature by providing a test of the rational voter hypothesis in a dynamic context.