Group size, member selection, and performance: Evidence from legislative elections in Brazil

This paper provides empirical evidence on the causal effects of group size on member selection and performance. Using data from local legislative elections in Brazil in a difference-in-differences framework, I explore an electoral reform that reduced the maximum number of candidates allowed in coalitions disputing legislative seats. The reform did not change the number of candidates and parties in the election, which was possible because in municipalities affected by the new cap parties reorganized into 21% more coalitions than would be expected without the reform. I discuss how the heterogeneity of the candidates combined with the coalitions’ adjustment to the reform led to the election of city councilors who were 17% wealthier, on average. Although the reform achieved the goal of reducing campaign costs, which fell by 9%, the election of wealthier politicians was an unintended consequence that weakened the representation of economically disadvantaged groups in the legislative body.