What is "single transferable vote"

n. A voting system where each voter lists the candidates in order of preference and there is provision to transfer the votes of the less popular candidates and a proportion of the votes of candidates who are elected with more than a certain quota.

The single transferable vote (STV) is a voting system designed to achieve proportional representation through ranked voting in multi-seat 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.

Hare–Clark is the name given to STV in lower house elections in two Australian states and territories, Tasmania and the Australian Capital Territory. The name is derived from Thomas Hare, who developed the system, and the Tasmanian Attorney General, Andrew Inglis Clark, who modified the counting method on introducing it to Tasmania. Hare–Clark has been changed to use rotating ballot papers (the Robson Rotation). The upper houses of New South Wales, Victoria, Western Australia and South Australia, and the Senate of Australia, use a variant of STV allowing " group voting".

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 calls it 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).