Approval voting

A political cartoon about the 1920 Greek referendum, depicting a voter at the ballot box being watched by the spirit of War. This shows the form of ballot boxes used in 19th–20th century Greece for approval voting.
On an approval ballot, the voter can select any number of candidates.

Approval voting is a single-winner electoral system where each voter may select ("approve") any number of candidates. The winner is the most-approved candidate.

Robert J. Weber coined the term "Approval Voting" in 1971.[1] Guy Ottewell described the system in 1977.[2] It was more fully published in 1978 by political scientist Steven Brams and mathematician Peter Fishburn.[3]

Description

Approval voting ballots show a list of the candidates running for that seat for each office being contested. Next to each name is a checkbox (or another similar way to mark "Yes" or "No" for that candidate).

Each candidate may be treated as a separate question: "Do you approve of this person for the job?". Approval voting lets each voter indicate support for one, some, or all candidates. All votes count equally, and everyone gets the same number of votes: one vote per candidate, either for or against. Final tallies show how many voters support each candidate, and the winner is the candidate whom the most voters support.

Ballots on which the voter marked every candidate the same (whether yes or no) usually have no effect on the outcome of the election. Each ballot separates candidates into two groups: those supported and those that are not. Each candidate approved is considered preferred to any candidate not approved, while the voter's preferences among approved candidates is unspecified, and likewise, the voter's preferences among unapproved candidates is also unspecified.

Approval voting can be considered a form of range voting, with the range restricted to two values, 0 and 1—or a form of majority judgment, with grades restricted to good and poor. Approval Voting can also be compared to plurality voting, without the rule that discards ballots that vote for more than one candidate.