Single transferable ballot

The single transferable vote (STV) is a voting system designed to achieve proportional representation through ranked voting in multi-seat organizations or constituencies (voting districts). Under STV, an elector (voter) has a single vote that is initially allocated to their most preferred candidate and, as the count proceeds and candidates are either elected or eliminated, is transferred to other candidates according to the voter's stated preferences, in proportion to any surplus or discarded votes. The exact method of reapportioning votes can vary (see Counting methods).

The system provides approximately proportional representation, enables votes to be cast for individual candidates rather than for parties, and—compared to first-past-the-post voting—reduces "wasted" votes (votes on sure losers or sure winners) by transferring them to other candidates.

STV is the system of choice of groups such as the Proportional Representation Society of Australia (which calls it quota-preferential proportional representation), the Electoral Reform Society in the United Kingdom and FairVote in the USA (which promotes a variant called ranked choice voting). Its critics contend that some voters find the mechanisms behind STV difficult to understand, but this does not make it more difficult for voters to "rank the list of candidates in order of preference" on an STV ballot paper (see Voting).

STV has had its widest adoption in the English-speaking world. As of 2010^[update], in government elections, STV is used for:

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