Mixed-member proportional representation
Mixed-member proportional representation is a mixed electoral system which combines local majoritarian elections with a compensatory tier of party list votes, which are used to allocate additional members in a way that aims to produce proportional representation overall. In most MMP systems, voters get two votes: one to decide the representative for their single-seat constituency, and one for a political party. Some countries use single vote variants of MMP, although this article focuses primarily on dual vote versions of MMP.
Ballot for electoral district 252, Würzburg, for the 2005 German federal election. Constituency vote on left, party list vote on right.
Proportional representation
Proportional representation (PR) refers to any type of electoral system under which subgroups of an electorate are reflected proportionately in the elected body. The concept applies mainly to political divisions among voters. The essence of such systems is that all votes cast – or almost all votes cast – contribute to the result and are effectively used to help elect someone – not just a bare plurality or (exclusively) the majority – and that the system produces mixed, balanced representation reflecting how votes are cast.
Activists campaigning for proportional representation in Canada in September 2013
Image: Canada election 2015