Ranked voting, also known as ranked-choice voting or preferential voting, refers to any voting system in which voters use a ranked (or preferential) ballot to select more than one candidate (or other alternative being voted on) and to rank these choices in a sequence on the ordinal scale of 1st, 2nd, 3rd, etc. Ranked voting is different from cardinal voting, where candidates are independently rated rather than ranked.
The most important differences between ranked voting systems lie in the methods used to decide which candidate (or candidates) are elected from a given set of ballots. Some of the most significant methods are described below.
Another (more cosmetic) difference lies in the format of the ballot papers. Some jurisdictions require voters to rank all candidates; some limit the number who may be ranked; and some allow voters to rank as many as they see fit, with the rest being lumped together at the end. Other rules (sometimes entailed by the method of determining a winner) are imposed in different cases.
The subject of this article should not be confused with instant-runoff voting, a specific form of ranked voting to which the US organization FairVote has attached the name 'ranked-choice voting'. Ranked voting is used in national or state elections in Australia, Ireland, two US states, New Zealand, Malta, Slovenia and Nauru.