Encyclopedia  |   World Factbook  |   World Flags  |   Reference Tables  |   List of Lists     
   Academic Disciplines  |   Historical Timeline  |   Themed Timelines  |   Biographies  |   How-Tos     
Sponsor by The Tattoo Collection
Runoff voting
Main Page | See live article | Alphabetical index

Runoff voting

Runoff voting is a voting system used in single-seat elections. It is used widely around the world, including in elections for the President of France and Finland, and especially in a political party's primary elections, in which it selects candidates to present to the public.

When restricted to two rounds, it is sometimes called the two round system or the second ballot. When the number of rounds is unlimited, then it is sometimes know as an elimination ballot.

Table of contents
1 Voting
2 An Example
3 Potential for Tactical Voting
4 Impact on factions and candidates
5 See also


In the preliminary election, voters select their preferred candidate. If one candidate reaches the election threshold (usually fifty percent of the positive votes plus one), they are elected.

Otherwise, in a two round system, the top candidates (usually the top two) are placed on a secondary ballot. Whoever receives the most votes on the second ballot is declared elected.

In an elimination ballot, successive rounds of voting are held until a candidate wins a majority of the positive votes. After each inconclusive round, those candidates at the bottom whose votes together do not add up to the votes of the next candidate are eliminated (so barring ties at least one candidate is eliminated each round).

Runoff voting can be condenced into a single preference ballot paper, at which point it becomes "Instant Runoff Voting" or an "Alternative Vote". A simplified model of a two round system is the "Supplementary Vote".

A runoff ballot is not the same thing as primary elections. In a runoff ballot, all candidates are placed on the inital ballot and all voters are allowed to participate in the vote, whereas primaries are generally internal measures within a political party.

An Example

Imagine an election for the capital of Tennessee, a state in the United States that is over 500 miles east-to-west, and only 110 miles north-to-south. In this vote, the candidates for the capital are Memphis, Nashville, Chattanooga, and Knoxville. The population breakdown by metro area is as follows:

If the voters cast their ballot based strictly on geographic proximity, the voters' sincere preferences might be as follows:

42% of voters (close to Memphis)
  1. Memphis
  2. Nashville
  3. Chattanooga
  4. Knoxville
26% of voters (close to Nashville)
  1. Nashville
  2. Chattanooga
  3. Knoxville
  4. Memphis
15% of voters (close to Chattanooga)
  1. Chattanooga
  2. Knoxville
  3. Nashville
  4. Memphis
17% of voters (close to Knoxville)
  1. Knoxville
  2. Chattanooga
  3. Nashville
  4. Memphis

Assuming each voter voted for their preferred city (for a more sophisticated approach, see below), the first ballot results would be as follows:

In a two round runnoff, Knoxville and Chattanooga are eliminated, while Nashville and Memphis advance to the second ballot.

The voters from Knoxville and Chattanooga prefer Nashville to Memphis, so the results of the second ballot would be:

Nashville would then be declared the winner.

Note on strategy: A two round runoff encourages candidates to unite to make the top two cut. Since Chattanooga and Knoxville both prefer each other second, knowing their divided vote might eliminate them both, they might work together before the election and decide for only Chattanooga to run. That would cause the defeat Nashville (third place) and Chattanooga could win the final runoff round against Memphis. Something similar would happen with a multi-round elimination ballot.

In an elimination ballot, Chattanooga would be eliminated after the first round, and the second round would be:

Nashville would then be eliminated and the third round of the elimination ballot would be:

So Knoxville would win.

Potential for Tactical Voting

The runoff system encourages voters to "compromise" by not voting for their favorite candidate in their first round. In the above two-round example, if all voters from Chattanooga "compromised" for Knoxville in the first round, Knoxville would advance to the second round, where it would defeat Memphis. This would be a better result for the Chattanooga voters than sincere voting would get them. The Memphis supporters voters could respond by voting for Nashville instead of Memphis as a way to prevent Knoxville or Chattanooga winning.

Runoff voting can also encourage voters to vote for "push-overs", in order to set up a more favorable second-round matchup.

Impact on factions and candidates

Between each round of voting, discussion and dealing is possible; policy concessions and withdrawals can be negotiated. Accordingly, runoff votes in some form are advocated as part of most deliberative democracy proposals. Other electoral reform and grassroots democracy advocates prefer instant-runoff voting which let larger groups participate in the process by ballot - the French participation of the whole electorate in a runoff vote is a rare exception and permits some dealing between parties who have lost and those who seek their support.

The one-ballot "instant runoff" proposals are the opposite of such 'deliberative' processes, as there is no time nor place for explicit discussion and dealing as the power relationships become clear. Polls can take the place of early rounds of balloting, but are nowhere near as statistically valid as a formal vote.

See also