Quote
"Contingency vote systems: the elector has only one vote under this voting system. On his ballot paper, he is asked to classify all the candidates standing in his constituency in order of preference. In the count, his vote will initially go to his or her first-preference candidate. Subsequently, that vote may be transferred to the second, third, etc preferred candidate. The aim of this voting method is to enable electors to qualify their choice, while avoiding the wastage of votes granted to candidates who would not be elected or who already have a sufficient number of votes to be declared elected. In practice, this type of voting method has invariably been used where there are individual candidatures. However, it could theoretically be applied to list-based ballots provided that the lists are closed. It should also be noted that contingency vote systems are only used for single-round ballots.
"
Cite
Cite