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Compared to other reform alternatives
IRV is in use in multiple countries in national, local, party, and non-governmental elections. Recent US Republican and Democratic presidential candidates Barack Obama, Howard Dean, John McCain and Dennis Kucinich support IRV. <!--this is one of many such criteria for which there are separate articles

Tactical voting
Like all multi-round election methods that eliminate candidates between rounds of counting, IRV fails the monotonicity criterion: a candidate should not be disadvantaged if some voters increase their support for the candidate, or conversely should not be rewarded by voters decreasing their support (when all other candidates retain their relative ordering). In IRV elections, the reallocation of ballot papers from an eliminated candidate can alter the balance of votes of the other candidates, making IRV sensitive to vote changes that alter which candidate is eliminated in a particular round.

Consider the following 3-candidate situation: candidate A wins the first round with most votes but no overall majority. The election progresses to a second round in which the votes from the eliminated candidate (C) are redistributed. Assume that the preference among these is for B over A; in other words, the majority of supporters of C gave an ordering C > B > A. In this situation, B may defeat A in the second round run-off.

A' backers can improve their chances by switching support to C (their arch-rival, given that C's supporters largely preferred B to A). If they are able to push C's totals just beyond B's (voting A > C > B instead of C > A > B), they can force B's elimination in the first round, clearing the way for A—as long as B's voters don't prefer C to A.

For tactical voters to employ this strategy in practice would require near-complete knowledge of how everyone else will vote: switching their allegiance to a rival in insufficient numbers affords no benefit to their candidate, while excessive support for their rival can eliminate their candidate prematurely. Austan-Smith and Banks argued, in 1991, that "monotonicity/nonmonotonicity in electoral systems is a nonissue." What fraction of possible (or likely) outcomes are non-monotonic under IRV is an open question.-->

Minority representation
Majority voting, whether or not it uses IRV, leaves many voters with a "representative" they oppose. The alternative of proportional representation voting methods enables most or all voters to elect representatives they support.

The Condorcet criterion
As with any runoff process where voters vote for only one candidate each round, IRV can fail to elect the Condorcet winner, meaning the candidate preferred to each other candidate in the field. In a three-candidate field, for example, suppose there is a candidate who defeats the other two candidates head-to-head, but is eliminated in the first round for having the fewest first choice rankings. The example above shows the 'Condorcet winner being eliminated after the field is reduced to three cities.

Runoff elections require a mixture of two measures of strength of a winning candidate: first preferences, or core-support; and later preferences, or compromise-appeal. Plurality elections, with one vote and no runoff option, reward core-support exclusively. Condorcet methods, with head-to-head competition and no elimination, strongly reward compromise-appeal, but unlike Borda, not to the point of disregarding majority rule. Runoff methods like IRV require some core-support in the early rounds to avoid elimination, and compromise-appeal to win the election in the final round. Still, IRV can elect a candidate other than the Condorcet winner even when the Condorcet winner has a greater number of first preferences, or core-support, than the candidate elected by IRV.

Although few governmental elections with IRV have been proven to fail to elect the Condorcet winner, the IRV election for mayor of Burlington, Vermont in 2009 provides an example. The Condorcet winner was in third place in first choices and was eliminated after the field was reduced to three candidates.

Contrasting IRV with other voting methods, voting systems with a Condorcet method will always elect a Condorcet winner in a race that has one. IRV is more likely to elect the Condorcet winner than plurality voting, however. For example, the California cities of Oakland, San Francisco and San Leandro in 2010 had a total of four elections in which the plurality voting leader in first choice rankings was defeated. In each case, the IRV winner was the Condorcet winner, including a San Francisco election in which the IRV winner was in third place in first choice rankings.

Robert's Rules of Order
The sequential elimination method used by IRV is described in Robert's Rules of Order Newly Revised, 10th edition. as an example of "preferential voting," a term covering "any of a number of voting methods by which, on a single ballot when there are more than two possible choices, the second or less-preferred choices of voters can be taken into account if no candidate or proposition attains a majority. While it is more complicated than other methods of voting in common use and is not a substitute for the normal procedure of repeated balloting until a majority is obtained, preferential voting is especially useful and fair in an election by mail if it is impractical to take more than one ballot. In such cases it makes possible a more representative result than under a rule that a plurality shall elect...."Preferential voting has many variations. One method is described ... by way of illustration." And then the instant runoff voting method is detailed.

Robert's Rules continues: "The system of preferential voting just described should not be used in cases where it is possible to follow the normal procedure of repeated balloting until one candidate or proposition attains a majority. Although this type of preferential ballot is preferable to an election by plurality, it affords less freedom of choice than repeated balloting, because it denies voters the opportunity of basing their second or lesser choices on the results of earlier ballots, and because the candidate or proposition in last place is automatically eliminated and may thus be prevented from becoming a compromise choice." Two other books on parliamentary procedure take a similar stance, disapproving of plurality voting and describing preferential voting as an option, if authorized in the bylaws, when repeated balloting is impractical: The Standard Code of Parliamentary Procedure and Riddick's Rules of Procedure.