Ranked-choice voting (RCV) is a ranked voting system used in some states and cities in the United States in which voters may prioritize (rank) their choice of candidates among many, and a procedure exists to count lower ranked candidates if and after higher ranked candidates have been eliminated, usually in a succession of counting rounds. In practice, there are several ways this can be implemented and variations exist; instant-runoff voting (IRV) and single transferable vote (STV) are the general types of ranked-choice voting systems used in the United States.