What Is the Optimal Constituency Size?

• In Event: Disproportionality, Inequality, and the Structure of Electoral Systems

Abstract

A growing body of scholarship suggests that population size scaling shapes democracy in fundamental ways. However, the electoral benefits of constituency population are mixed. Several studies have shown, on the one hand, that turnout decreases in more population electoral districts, which suggests that smaller districts promote democratic participation and engagement. On the other hand, research shows that elections become more competitive in more population electorates, which implies that larger districts promote democratic contestation. In this paper, I propose a logical model that gives equal weight to electoral competition and participation in order to identify the district population size at which both values are maximized. I fit my model empirically using a dataset on US and Canadian mayoral elections, which includes more than 3000 municipal election results between 2017-2022, with population sizes ranging from 3 to more than 1 million. The results suggest that the balance between participation and contestation is maximized when population is between 1,000 and 10,000. The results have important implications for democracy and democratic reforms.

Author

• Alex Keena, Virginia Commonwealth University