Party list proportional representation

Party-list proportional representation systems are a family of voting systems emphasizing proportional representation (PR) in elections in which multiple candidates are elected (e.g., elections to parliament) through allocations to an electoral list. They can also be used as part of mixed additional member systems.

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, as in Albania, Argentina, Turkey, and Israel; or for candidates whose vote total will pool to the party, as in Finland, Brazil and the Netherlands; or for a list of candidates, as in Hong Kong. Voters in Luxembourg's multi-seat constituencies can choose between voting for a complete list of candidates of a single party ("list vote") or voting for individual candidates from one or several lists ("panachage").

The order in which a party's list candidates get elected may be pre-determined by some method internal to the party or the candidates (a closed list system) or it may be determined by the voters at large (an open list system) or by districts (a local list system).

Many variations on seat allocation within party-list proportional representation exist. The two most common are:

List proportional representation may also be combined in various hybrids, e.g., using the additional member system.

List of main apportionment methods (most proportional to least proportional):

...
Wikipedia