Apparentment is the name given to the system, sometimes provided for in elections

Voting system

A voting system or electoral system is a method by which voters make a choice between options, often in an election or on a policy referendum....

 conducted according to the party-list proportional representation

Party-list proportional representation

Party-list proportional representation systems are a family of voting systems emphasizing proportional representation in elections in which multiple candidates are elected...

 system, which allows parties to specify electoral alliances. The system has been used in Switzerland

Elections in Switzerland

Elections in Switzerland gives information on election and election results in Switzerland.Switzerland elects on national level a head of state - the Federal Council - and a legislature. The Federal Assembly has two chambers...

 since 1919.

In list PR systems, seats are awarded for each quota of votes obtained. Any votes excess to the quota are lost. Under apparentment, parties combine their vote excess, which may yield an additional full quota and candidate elected.

The system introduces an element of ordinality. It is akin to a pre-specified ranking in a preferential voting system like Alternative Vote or Single Transferable Vote

Single transferable vote

The single transferable vote is a voting system designed to achieve proportional representation through preferential voting. Under STV, an elector's vote is initially allocated to his or her most preferred candidate, and then, after candidates have been either elected or eliminated, any surplus or...

, as is used with the above-the-line system in Australian elections.