Preferential votes and minority representation in open list proportional representation systems

Under open list proportional representation, voters vote both for a party and for some candidates within its list (preferential vote). Seats are assigned to parties in proportion to their votes and, within parties, to the candidates obtaining the largest number of preferential votes. The paper examines how the number of candidates voters can vote for affects the representation of minorities in parliaments. I highlight a clear negative relationship between the two. Minorities are proportionally represented in parliament only if voters can cast a limited number of preferential votes. When the number of preferential votes increases, a multiplier effect arises, which disproportionately increases the power of the majority in determining the elected candidates.