Effects of the Representation System on the Distribution of Votes and Seats in Latin America (1990-2019)

Abstract

One of the main consequences of the legal rules that govern electoral systems is that they establish the conditions for the conversion of votes into seats. Based on various public sources of information, this essay constructs indicators on the effects of the rules adopted in the electoral systems of Latin America in the period 1990-2019 in terms of the fragmentation of votes and seats. The evidence analyzed shows that there is no defined and constant pattern that reflects that the adoption of a proportional representation system results in a different fragmentation than that which occurs when a mixed system is available. The lower fragmentation of the vote than of seats does not turn out to be a product of the presence of partisan alliances. The fragmentation of voting in mixed systems has increased systematically, a situation that does not occur in the case of proportional systems.