Approval Voting vs.
Instant Runoff Voting

Plurality voting suffers from two serious flaws.  The first is lack of majority rule.  The second is the “spoiler” problem:  many voters have incentive not to vote for their favorite candidate because doing so might lead to the election of their least favorite candidate.  As a result, many voters choose not to vote for their favorite candidate and instead vote for a less preferred candidate who has a chance of winning. 

Many voting systems improve upon plurality voting.  Click for brief descriptions of some of these systems.

Approval voting is one such system.  In approval voting, voters vote for all candidates they approve of.  The candidate with the highest number of votes wins the election.  Benefits of this system are that it is extremely simple to explain to the voter – instructions simply state, “Vote for 1 or more candidates” – and all existing voting equipment can accommodate this system.

The Center for Voting and Democracy believes that both approval voting and instant runoff voting improve upon plurality elections and two-round runoff elections, but we prefer instant runoff voting.

Dr. Kenneth Arrow won a Nobel Prize for proving that no perfect voting system exists.  This means that all systems have flaws, and all systems sometimes lead to outcomes that violate our common sense notions of fairness.  For example, in plurality voting if two similar candidates split a majority of the vote, in a plurality election, a candidate strongly opposed by a majority of the voters can be elected.  This violates the important criteria of majority rule.

Bearing in mind that no system is perfect and that all systems have their advantages and disadvantages, we believe that instant runoff voting is superior to approval voting for public elections for several reasons.

  • Approval voting does not solve the spoiler problem.  V oting for your second choice candidate can in some cases lead to the defeat of your favorite candidate.  (This problem is less severe than in plurality voting, but instant runoff voting does a better job of addressing the spoiler problem.)  Campaigns would urge – quietly at least – their supports to “bullet” vote for their candidate only, and approval voting would thus tend to revert back to plurality voting.  Approval voting is unlikely to work in practice as it is supposed to work in theory.
  • Approval voting forces voters to cast equally weighted votes for candidates they approve of.  Voters cannot indicate a strong preference for one candidate and a weak preference for another. Voters in fact almost always will have different degrees of support for different candidates.
  • Approval voting would challenge our notions of majority rule: Adoption of approval voting could cause the defeat of a candidate who was the favorite candidate of 51% of voters. If this result were to happen the system would likely be repealed.

These reasons help explain why instant runoff voting is used for national elections in several elections and why legislation to adopt instant runoff voting is gaining such widespread support in the United States. As far as we know, approval voting is not used in any public elections in the United States or elsewhere, although in the former Soviet Union a form of "disapproval voting" was used:  voters crossed out all candidates they disapproved of.

For more information, read a letter in Science magazine from Rob Richie, Terry Bouricius, and Philip Macklin on Approval Voting versus Instant Runoff Voting.