Party-list proportional representation (PLPR) systems are a family of Partisan system used in multiple-winner elections (e.g. elections to parliament), emphasizing proportional representation. In these systems, parties make lists of candidates to be elected, and seats get allocated to each party in proportion to the number of votes the party receives. Voters may vote directly for the party, like in Israel, or they may vote for candidates and that vote will pool to the party, like in Turkey and Finland. The order in which the party's list candidates get elected may be pre-determined by some method internal to the party (a closed list system) or they may be determined by the voters at large (an open list system).
There are many variations on seat allocation within party-list proportional representation. The three most common are:
- The d'Hondt method, used in Israel, Austria and Poland, among other places;
- The Sainte-Laguë method, used in many Scandinavian countries, New Zealand, and the German Federal State Bremen; and
- The largest remainder method.
List PR may also be combined in various hybrids (e.g. using the Additional member system).
The unmodified Sainte-Laguë method and the LR-Hare method rank as the most proportional followed by LR-Droop; single transferable vote; modified Sainte-Laguë, d'Hondt and largest remainder Imperiali. While the allocation formula is important, equally important is the district magnitude (number of seats in a constituency). The higher the district magnitude, the more proportional a proportional electoral system becomes.
Since a party list method proportionally allocates the seats in an assembly (like a legislature), it may also be used to proportionally divide seats among states in a federal assembly. When a party list method is used for this purpose, it is called an apportionment method. The use of the Huntington-Hill method to allocate seats of the United States House of Representatives is an example of apportionment.
One criticism of PLPR is that sometimes, the allocation of seats to factions within a party is disproportional. This can be because of the use of an open list system, because SNTV is usually used to determine which candidates win, and under honest voting, this can lead to very disproportionate outcomes. This is one reason why some prefer voting methods like STV and Asset voting.
- Mike Ossipoff's site on List Proportional representation
- Site of the Independent Commission reviewing the effects of PR in the UK