Hare-Clark system

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.

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 as well as the Australian Senate have used a variant of STV that has historically allowed for the use of "Group voting tickets". Although the New South Wales Legislative Council (in 2003) and the Senate (in 2016) have reformed their electoral systems to abolish group tickets and instead require manual allocation of preferences.

...
Wikipedia