Parallel voting describes a mixed
voting system where voters in effect participate in two separate elections for a single chamber using different systems, and where the results in one election have little or no impact on the results of the other. Specifically, it usually refers to the semi-proportional system used in
Japan,
South Korea,
Taiwan, some regions of
Russia and elsewhere, sometimes known as the
Supplementary Member (SM) system or, by some political scientists,
Mixed Member Majoritarian (
MMM), which combines
first-past-the-post voting (FPTP) with
party-list proportional representation. Parallel voting or MMM is distinct from
mixed member proportional representation (MMP) where a single election takes place, and the party vote determines what share of seats each party will receive in the legislature to "top up" its constituency seats.