Do some electoral systems select better politicians than others? Single- vs dual-ballot elections

I use the discontinuous allocation of single and dual-ballot rules across mayoral elections in Brazil to compare politicians fielded and elected in these systems. Dual-ballot candidates in general are not statistically different from their single-ballot counterparts in terms of age, education and occupational skill. Parties field female candidates at the same rate in both systems, but dual-ballot elections have less women in the top two and three positions, on average. These candidates raise and spend, on average, the same amount of resources in the electoral campaign and the rate at which they win and/or run for reelection is also similar. Interestingly, the only difference in performance found between the two types of mayors is in the attraction of discretionary transfers, which is larger in dual-ballot municipalities, but only in election years when mayors are eligible for reelection. Taken together, these results indicate that the experience demanded from candidates in major parties entering dual-ballot elections may translate into unobserved political skills that are required to deal with the electoral process in dual-ballot. That, by itself, punishes female candidates to the extent to which women's participation in politics has been historically low.