Optional preferential voting
Optional preferential voting (OPV) is a type of preferential voting system under which voters indicate the order of their preferences by numbers. Full-preferential voting requires a preference to be indicated for each candidate. Under OPV, voters may choose to mark a preference for as many candidates as they want. Although complete numbering is not required under OPV, single-preference voters may be required to use a '1' rather than a tick or cross. Some jurisdictions allow ticks or crosses as the voter's intention is clear. Some jurisdictions use semi-optional preferential voting, in which the expression of a minimum number of preferences is required.
In both the Tasmanian House of Assembly and the Tasmanian Legislative Council, semi-optional voting is used, with a minimum number of preferences required to be expressed; but there is no requirement to complete the entire ballot paper. Elections for all other Australian lower houses use full-preferential voting. In the Victorian Legislative Council, semi-optional voting is used if a voter chooses to vote below the line. Voting above the line requires only a ‘1’ being placed in one box, and group voting tickets voting has applied since 1988.
The Australian Senate voting reform of 2016 switched from full-preferential voting to semi-optional. A minimum number is specified in the instructions on the ballot paper. Since in the past a single number '1' above the line was formal, that is still a valid vote even though voters are encouraged to number six squares.
The ranked-choice voting system used by Maine, USA, can be considered optional-preferential as voters are allowed to rank just one candidate. The system also allows voters to skip one ranking (e.g. marking a first choice and a third choice, but not a second choice). In that case, the next ranking would be advanced to the next highest ranking, but more than one skip exhausts the ballot.
- Optional Preferential: Elections NSW
- Northern Territory Adopts Optional Preferential Voting and Bans Campaigning Near Polling Places: Antony Green ABC 11 February 2016
- "The Queensland Electoral System". Queensland Parliament. Retrieved 15 December 2017.
- Burke, Gail (22 April 2016). "Compulsory preferential voting returns to Queensland as Parliament passes bill for more MPs". Australian Broadcasting Corporation. Retrieved 15 December 2017.