Single Transferable Vote

What: The single transferable vote (STV) is a voting system designed to achieve proportional representation through ranked voting. Under STV, an elector's vote is initially allocated to his or her most preferred candidate, and then, after candidates have been either elected or eliminated, any surplus or unused votes are transferred according to the voter's stated preferences. 

Why: The system minimizes "wasted" votes, provides approximately proportional representation, and enables votes to be explicitly cast for individual candidates rather than for closed syndicate of contestants. 

How: It achieves this by using multi-seat constituencies (different regions) and by transferring votes to other eligible candidates that would otherwise be wasted on sure losers or sure winners.

Andrew Inglis Clark

ICAI Elections: A modified version of STV, known as the Hare–Clark system, is used in ICAI elections. The name is derived from Thomas Hare, who initially developed the system and the Tasmanian Attorney General, Andrew Inglis Clark, who worked to have a modified version introduced. 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' in an STV ballot paper.

Thomas Hare

History of STV: The concept of transferable voting was first proposed by Thomas Wright Hill in 1821. The system remained unused in real elections until 1855, when Carl Andræ proposed a transferable vote system for elections in Denmark. Andræ's system was used in 1856 to elect the Danish Rigsraad, and by 1866 it was also adapted for indirect elections to the second chamber, the Landsting, until 1915.