Mixed-member proportional representation

Mixed-member proportional representation, also termed mixed-member proportional voting and commonly abbreviated to MMP, is a voting system originally used to elect representatives to the German Bundestag, which has also been adopted by New Zealand, Lesotho, and Romania. MMP is a hybrid method that uses party list PR as its proportional component, and currently (but not necessarily) FPTP as its district component. It is considered a mixed system (also known as a hybrid system or a semi-proportional representation system), which is a distinct voting system. "An electoral system is "mixed" if more than one formula is employed to distribute legislative seats."

Mixed member proportional representation (MMP), is a hybrid, two-tier, system combining a non-proportional district election (currently but not necessarily on a single-winner basis) and a compensatory regional or national party list PR one. MMP is similar to forms of proportional representation (PR) in that the overall total of party members in the elected body is intended to mirror the overall proportion of votes received; it differs by including a set of members elected by geographic constituency who are deducted from the party totals so as to maintain overall proportionality. MMP is similar to the additional member system (AMS) used in some parts of the United Kingdom, which has no overhang seats or balance seats and consequently is not perfectly proportional. Voters have two votes, one for their single-member district and one for the party list, the party list vote determining the balance of the parties in the elected body.Biproportional apportionment, first used in Zurich in 2006, is a hybrid method for adjusting an election's result to achieve overall proportionality.