Mixed-member majoritarian representation

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Mixed member majoritarian representation (MMM) is type of a mixed electoral system combining majoritarian (or plurality) and proportional methods, where the disproportional results of district contests using a plurality voting system or other, usually first-past-the-post voting (a system called majoritarian in this context), are completely separate from the proportional component. Mixed member majoritarian systems are therefore described as semi-proportional representation, and are usually contrasted with mixed-member proportional representation (MMP) which aims to provide proportional representation via additional compensation ("top-up") seats.

The most common type of MMM system is the supplementary member (SM) system (a form of parallel voting), whereby representatives are voted into a chamber using at least two different systems independently of each other. Most commonly this combines first-past-the-post (single member plurality) voting (FPTP/SMP) with party-list proportional representation (list-PR). The system has been applied in the election of national parliaments as well as local governments in various places such as Taiwan, Lithuania, Russia and Kazakhstan. While FPTP with list-PR is the most common pairing in parallel systems, any other combination is effectively possible and therefore not all parallel voting systems are mixed-member majoritarian (and not all effectively MMM systems are strictly parallel - non-compensatory), however as most of them used in practice are, the terms are sometimes used interchangeably.