Electoral Systems, Ethnic Heterogeneity and Party System Fragmentation

Taking into proper account the geographic distribution of ethnic groups and the operation of electoral systems within individual countries reveals that the impact of ethnic diversity and electoral systems on the number of parties has been underestimated. Contrary to earlier findings, this study reveals that ethnic diversity spurs party proliferation in countries with both majoritarian and proportional electoral systems, though the effect is stronger in the latter. The insights gained here provide a theoretically derived measure of ethnic diversity that is useful for estimating its effect on specifically political phenomena and generating an improved holistic measure of the impact of electoral systems. More crucially, the results indicate that electoral system designers have a greater capacity to structure electoral outcomes. The results rely on multivariate models created using a new database with election results from 1990 through 2011 in sixty-five free democracies.