In an election based on preferences, voters are presented with a list of candidate options. The aim of is to elect a single winner among all options. For that, each voter must rank the options, and cast a vote using this ordered preference list (ties are allowed).

The algorithm used to determine the outcome of the election guarantees that if there is a candidate who is preferred by a majority over every other candidate in pairwise comparisons, then this candidate will be the winner.

Reference: Markus Schulze, "A new monotonic, clone-independent, reversal symmetric, and condorcet-consistent single-winner election method", Social Choice and Welfare, volume 36, number 2, page 267–303, 2011.