Approval Voting


What is Approval Voting?

Approval Voting is a voting method that allows voters to vote for any number of candidates. The candidate with the most votes wins. Approval Voting is most often discussed in the context of single-winner elections, but variations can also be applied to multi-winner “at large” elections. 


What would the ballot look like?

Approval Voting requires no substantive change to ballots. The printed directions simply change to indicate that the voter may select any number of candidates. Here is an example ballot where the voter has selected three candidates by darkening the circles next to their names.

Approval Voting highlights:

  • More expressive
  • No vote splitting or spoilers
  • You can never get a worse result by voting for your favorite
  • Significantly fewer spoiled ballots
  • Ballots look the same, except the rules indicate that you may vote for any number of candidates
  • Results are still easy to understand: a simple list of the candidates along with how many votes they received
  • Tends to elect candidates who would beat all rivals head-to-head
  • Tends to elect more moderate winners
  • Alternate candidates get a more accurate measure of support

How would Approval Voting results differ from Plurality Voting results?

Political scientists in France and Germany conducted two large-scale Approval Voting surveys based on their real elections. These studies further support the positive effects of Approval Voting. For instance, voters using Approval Voting largely chose to vote for more than one candidate (i.e. they didn’t widely bullet vote). Also, the candidates showing scant support under Plurality Voting were better represented under Approval Voting. Their supporters were able to safely vote for them, even if they had also cast votes for more electable compromise candidates.

How will Approval Voting affect spoiled ballots?

Approval Voting experimentally results in about a fifth as many spoiled ballots. The only way to spoil an Approval ballot is to make the ballot unreadable—rather difficult. In fact, in the French and German studies referenced above, fewer than 1 in 200 ballots were spoiled.

Plurality Voting ballots are treated as spoiled whenever voters mark more than one candidate. The fact that voters do this tells us that they have more to say than Plurality Voting permits. Consequently, in the 2000 U.S. elections, nearly two million ballots were spoiled—almost 2%.

Does Approval Voting help major parties or minor parties?

While this may sound impossible, we contend that Approval Voting is fairer to both major and minor parties. Under the current system, popular major party candidates sometimes lose when a strong minor party or independent candidate draws some of the support that would have otherwise been theirs. Approval Voting addresses this by allowing supporters of alternative candidates to also support a more electable frontrunner as a compromise.

Additionally, alternative candidates get an accurate level of their support. One alternative voting experiment surveyed voters at polling places in Manhattan’s 69th State Assembly District. The group was granted credentials from the NYC Board of Elections to conduct the exit-poll style experiment inside the city’s official polling places. The experiment compared Plurality Voting (traditional “vote for one” method) with Approval Voting, Score Voting and Instant Runoff Voting. Below are graphs revealing the totals for these four systems.

Let’s first look at the Plurality Voting results, to establish a baseline.

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While this district was clearly not representative of the overall American electorate, note the relative strength of the minor party candidates compared to the major party candidates. For instance, Green Party candidate Jill Stein received one vote for about every 27 votes for Obama. (The study authors note that their results were consistent with the official election results.)

Now compare to Approval Voting.

Screen Shot 2013-12-05 at 9.42.22 PMThe Green Party now receives 58% as much support as the Democratic Party. This is over a 15x improvement in the Green Party’s strength relative to the Democratic Party, compared to where they were with Plurality Voting. The other minor party and write-in candidates also fared dramatically better.

See our in-depth article on Approval Voting and independents/third parties here. See how Approval Voting plays in with Duverger’s Law here.

Is Approval Voting vulnerable to tactical voting?

Approval Voting is highly resistant to tactical voting, including bullet votingTactical voting is when voters don’t cast purely honest ballots. Here’s a closer look on how Approval Voting resists the negative effects of tactics.

Does Approval Voting violate one person, one vote?

No. The term “one person one vote” refers to the weight of votes, not to how votes are expressed.

The U.S. Supreme Court made the “one person one vote” rule explicit in Reynolds v. Sims (377 U.S. 533). The rule stated that no vote should count more than any other so that it has unequal weight. This unequal weight would violate the Equal Protection Clause of the Constitution. And it was Baker v. Carr (369 U.S. 186) that extended the Equal Protection Clause to districting issues. In Reynolds, the state of Alabama set up its districts so that they varied wildly in population. The districting was so bad that it gave some voters’ ballots as much as 41 times more weight than others. Because the weights of the ballots were different between districts, that violated the “one person one vote” rule.

A common misconception is that Approval Voting gives more weight to voters who vote for more candidates. To see why this isn’t the case, imagine a tied election between a liberal and two conservatives. Bob casts a vote for the liberal, while Alice casts an opposing vote for the two conservatives. After Bob and Alice have voted, the election is still tied. Bob and Alice have an opposite but equal effect on the election. Another way to think of it is that if you vote for all candidates, that has the same effect as not voting at all. The key here is that no voter has an unfair advantage. Effectively, every voter casts an “aye” or “nay” vote for every candidate.

Finally, consider that voters are already allowed to vote for multiple candidates in “at large” races. For instance, a city council may simultaneously elect three representatives. Some voters may vote for three candidates, while others may vote for only one or two candidates.

Does Approval Voting increase voter satisfaction?

Computer simulation studies show that Approval Voting is superior to IRV as measured by “Bayesian regret“, an objective “economic” measure of average voter satisfaction. The following graph, adapted from page 239 of William Poundstone’s book Gaming the Vote displays Bayesian regret values for several different voting methods, as a function of the amount of tactical voting.

Bayesian regret

Where has Approval Voting been used?

Approval Voting is used to elect the Secretary General of the United Nations.

In 1990, Oregon used Approval Voting in a statewide advisory referendum on school financing, which presented voters with five different options and allowed them to vote for as many as they wished.

Approval Voting has been used in internal elections by the political parties in some US states, such as Pennsylvania, where a presidential straw poll using Approval Voting was conducted by the Democratic State Committee in 1983.

Approval Voting is also used by the state Libertarian Party in Colorado and Texas.

The Pirate Party (Piratenpartei) of Germany has been using Approval Voting for years to elect leaders, as well as to nominate their party lists. While it may have an unusual name, the party has already achieved significant political success. For instance, they won 10% (15 of 152) of the seats in the Berlin parliament elections in September 2011. Thus these are politically consequential, in many cases, highly contentious elections. You can see several sample results here, indicating that Approval Voting seems to have worked quite well. Sebastian Nerz, former president of the German Pirate Party, said:

I think that the Approval Voting system is working quite well! Most party members have no problems understanding the system itself, voting is fast and intuitiv [sic]. I know that several other systems are used by different parts of the Pirate Party Germany (e.g some districts use a simple Plurality voting system because it is easier if there are only few candidates). But Approval Voting is by far the most common voting system.

Approval and Score Voting were the foundation of government in renaissance Venice, and Ancient Sparta, respectively. These were two of the longest lasting (perhaps the two longest lasting) democracies ever.

Cardinals used Approval Voting for centuries to elect the Catholic Pope (at the time the most powerful elected person in the world).

Several large organizations, with membership well in excess of the number of citizens in many US cities, use Approval Voting:

  • Mathematical Association of America (MAA), with about 32,000 members;
  • American Mathematical Society (AMS), with about 30,000 members;
  • Institute for Operations Research and Management Sciences (INFORMS), with about 12,000 members;
  • American Statistical Association (ASA), with about 15,000 members;

Smaller societies that use Approval Voting include the Society for Judgment and Decision Making, the Social Choice and Welfare Society, the International Joint Conference on Artificial Intelligence, the Public Choice Society, and the European Association for Logic, Language and Information. Additionally, the Econometric Society has used Approval Voting (with certain emendations) to elect fellows since 1980; likewise, since 1981 the selection of members of the National Academy of Sciences at the final stage of balloting has been based on Approval Voting.


All told, at least several hundred thousand individuals have had direct experience with approval Voting.

What attempts have been made to enact Approval Voting in public elections?

In 1987, a bill to enact Approval Voting in certain statewide elections passed the Senate but not the House in North Dakota.

In January of 2011, representatives in New Hampshire proposed HB 240, which would have implemented Approval Voting for all statewide offices and presidential primaries.

In January of 2013, two Colorado senators, a Democrat and a Republican, proposed SB 13-065. This bill would have given all Colorado municipalities the right to adopt Approval Voting for non-partisan elections. The bill was supported by Colorado Secretary of State Scott Gessler (R). Here is a message he posted on Twitter. (This should in no way be interpreted as an endorsement of Scott Gessler.)

Screen Shot 2013-02-03 at 11.58.39 PM

A news piece summarized the result as follows [highlighting ours]:

Senate Bill 13-065 – This measure would have allowed local governments, including school boards, to use “approval voting” in nonpartisan elections. Approval voting is a system in which voters may vote for as many candidates as they want. Despite bipartisan sponsorship and endorsements from both Common Cause and GOP Secretary of State Scott Gessler, the Senate State Affairs Committee killed the bill on a 3-2 vote.

In October, 2013, petitioners in Oregon launched a ballot initiative drive to establish a “unified primary election” in place of Oregon’s current closed partisan primary.  This type of primary lets voters use approval voting to choose any number of candidates irrespective of party and advances the top two (regardless of party) to the general election.

But what about Instant Runoff Voting?

Our extensive analysis over the years overwhelmingly supports the view that Approval Voting is a much simpler and more democratic system than IRV. The results of Approval Voting elections are also much easier to understand than the numerous rounds of vote transfers that IRV utilizes. In an Approval Voting election, you would only see approval percentages and total votes for each candidate — much simpler than IRV. Don’t take our word on it. Click below for the Oakland 2010 IRV election results. Do you think voters easily understood this?

Where can I learn more about Approval Voting?

Steven Brams, an NYU political science professor from Concord, describes Approval Voting in layperson-friendly terms here.

Matt Gonzalez, Ralph Nader’s former running mate in 2008, generously placed one of our essays on his blog. It discusses Approval Voting, Score Voting, Instant Runoff Voting, and Top-Two Runoff. It can be found here.

Warren Smith, a Princeton math Ph.D. who has researched voting issues for over a decade, gives this detailed account of Approval Voting history.