Mixed-member majoritarian representation

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Mixed-member majoritarian representation (MMM) is type of a mixed electoral system combining winner-take-all and proportional methods, where the disproportional results of the winner-take-all part are dominant over the proportional component. Mixed member majoritarian systems are therefore categorized under semi-proportional representation, and are usually contrasted with mixed-member proportional representation (MMP) which aims to provide proportional representation 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. Therefore, not all parallel voting systems are mixed-member majoritarian (and not all MMM systems are strictly parallel - non-compensatory), however as most of them used in practice are, the terms are sometimes used interchangeably.

More unusual types of mixed-member majoritarian system are used in Pakistan, Italy and Hungary, and a de facto MMM system is used in South Korea.^[a]

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