Supplementary Vote

Supplementary vote

The supplementary vote (SV) is a variation of the contingent vote in which the voter ranks only two of the candidates in order of preference. It is used nowhere else in the world aside from some elections in England and Wales. If a voter's first-choice candidate is eliminated but their second choice is one of the two remaining candidates, their vote is transferred to the second-choice candidate. This means that the winning candidate has the support of a majority of voters who expressed a preference among the top two, although not necessarily a majority of votes cast in the first count. Unlike most other ranked choice methods, a voter must guess correctly which of the candidates will emerge in the top two for their second choice to be effective. John Curtice has said that it forces the supporters "of smaller parties to work out which of the two main candidates was most likely to appear in a runoff".