In a recent conversation with an IRV supporter I asked the question:
What cases would you accept as failure of IRV?
They answered:
Where the general public (or a significant fraction of it) failed to accept the results as legitimate, or at least beyond question. The 2000 and 2004 Presidential elections are examples of failed elections. San Franciso's election was heralded as a success.
I didn't know that 2004 was widely regarded as illegitimate.
They also believe that IRV has never failed to produce a fully satisfactory result. Can anyone provide evidence to the contrary?
I'm sure "satisfactory result" is already defined as "IRV winner", but here goes:
(1) Australian lower house: District elections are two-party races, with Labour on the left and Liberal/National on the right, despite whatever multiparty system exists in the PR-elected Senate. Although a two-party race doesn't provide much opportunity for an IIA or monotonicity failure, some would view the absence of true multiparty competition as the real failure.
Also, the prevalence of "how to vote" cards in Australia is often cited as an IRV-induced problem.
(2) San Francisco 2004: Of the four Supervisorial races tallied using IRV, none elected a candidate with a majority of votes. In one of the races, the winner only received about 30% of the original vote. The main cause appears to be that voters were only allowed to rank three choices, even though there were many more than three candidates.
In all four cases, the IRV winner agreed with the first-choice Plurality tally. Although IRV supporters are claiming that this is "positive"-- that IRV didn' produce "unexpected" results-- it is probably a predictable result of the three-choice limitation (the fewer choices allowed, the closer the result will be to Plurality). Also, the three choice restriction would likely have masked any Condorcet/IIA/monotonicity failures.
(3) California gubernatorial race, 2002: Although IRV wasn't used (it's difficult to show actualy IRV failures when it hasn't been adopted), the primary/general election was similar enough to a runoff to show what would have happened under IRV. The Republican primary featured Simon and Riordan, while Davis ran opposed as the Democratic incumbent. Riordan was eliminated in the primary, even though he was viewed as a head-to-head favorite against either of the other two candidates. Davis won, setting the stage for a successful recall election a year later.
Ironically, a similar situation arose in the 2003 recall election, with McClintock and Schwarzenegger replacing Simon and Riordan. Since this was a single-round election, the need for strategy was obvious and Republicans overwhelmingly backed the moderate candidate.
(4) Louisiana 1998(?) governor's race-- similar to California 2002. ---- Election-methods mailing list - see http://electorama.com/em for list info
