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).