View source for Single Transferable Vote

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).[1] Under STV, an elector (voter) has a single vote that is initially allocated to their most preferred candidate. Votes are totalled and a quota (the number of votes required to win a seat) derived. If their candidate achieves quota, he/she is elected and in some STV systems any surplus vote is transferred to other candidates in proportion to the voters' stated preferences. If more candidates than seats remain, the bottom candidate is eliminated with his/her votes being transferred to other candidates as determined by the voters' stated preferences. These elections and eliminations, and vote transfers if applicable, continue until there are only as many candidates as there are unfilled seats. The specific method of transferring votes varies in different systems. [https://en.wikipedia.org/wiki/Single_transferable_vote From Wikipedia]