# Single non-transferable vote

SNTV is choose-one FPTP voting applied to the multi-winner context. It is a semi-proportional method.

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SNTV passes a very weak form of Droop-PSC: if a group of voters with more than k Droop quotas evenly distributes their votes between k candidates, they can guarantee all k candidates will be elected. This is because there can at most be ${\displaystyle {\text{number of winners}}+1}$ Droop quotas in an election. Thus when k candidates have a Droop quota, at most ${\displaystyle {\text{number of winners}}-k+1}$ other candidates can have a full Droop quota as well.

For example, if there are 3 seats and 100 voters, and 2 candidates each have an exact Droop quota (25 votes), then either only one other candidate has more votes than the 2 (more than 25), meaning the 2 will be among the top 3 candidates (since if three candidates have over 75 votes together, then that means any other candidate must have fewer than 25 votes), or two other candidates also have 25 votes each, resulting in a tie.

By analog to Duverger's law, SNTV in n-seat districts tends to produce (n+1)-party rule.[1]

## Notes

SNTV can be combined with Party List by allowing each voter to give their vote to a party or to a candidate; the parties can each be allocated a certain number of seats, while independents can still win on their own. Note that this is possible even in the single-winner case (where SNTV is equivalent to the common choose-one FPTP voting method) to ensure that a plurality or majority elect someone from their preferred group of candidates, if there are many candidates in that group splitting the vote. The cast votes can also themselves be used to decide who within the Party List should win i.e. the candidates on the list with the most votes can be prioritized.

## References

1. Reed, Steven R. (1990). "Structure and Behaviour: Extending Duverger's Law to the Japanese Case". British Journal of Political Science. 20 (3): 335–356. doi:10.1017/S0007123400005871. JSTOR 193914.