The Effects of the 2015 Electoral Reform on the Chilean Party System

Abstract

In 2017, there was the launching of the inclusive proportional electoral system for the elections of both Representatives and Senators in Chile. This new electoral system replaced the binominal electoral system, introducing new incentives to the electoral contest and generating changes in the political system. After two electoral processes with this new electoral system – legislative elections of 2017 and 2021 – one can evaluate the effects of that reform on the party system. We analyze the conformation of the House of Representatives in 4 electoral processes, two with the binomial system-2009 and 2013-and two others with the new system. With a sample of 3,115 candidates and 550 elected Representatives, we measure the Effective Number of Parties (NEP) and the Effective Number of Lists (NEL) for the 2009-2021 period. Our findings include a sustained increase in the fragmentation of the Chilean party system, which could lead to complications for its democratic process.