A mixed single vote (MSV) is a type of ballot in mixed-member electoral systems, where voters cast a single vote in an election, which is used both for electing a local candidate and as a vote for a party affiliated with that candidate according to the rules of the electoral system. Unlike most mixed proportional and mixed majoritarian systems (such as parallel voting) where voters cast two votes, split-ticket voting is not possible under MSV. This significantly reduces the possibility of manipulating compensatory mixed systems, at the price of reducing voter choice. An alternative based on the mixed single vote that still allows for indicating different preferences on different levels is the mixed ballot, which functions as a preferential (mixed) single vote.
With MSV, voters usually cast their single vote for a local candidate in a single-member district (SMD) and then all votes (or just the wasted votes, depending on the system) from this lower tier are added to distribute seats between upper tier candidates, typically national party lists. How proportional the outcome is depends on many factors including the vote transfer rules (which votes are recounted as party list votes), whether there is a seat linkage, and other parameters (e.g. the number of list seats) used in the system. MSV systems originate from Germany and variations are currently used in Bolivia, Lesotho and Hungary for local elections in larger municipalities.
