Instant Runoff (IRV) voting system (Executive summary)

  1. Range voting is simpler than IRV.
  2. Range voting is more expressive than IRV.
  3. Range voting works on every voting machine in the USA, including noncomputerized ones, right now, without modification and without reprogramming. But IRV cannot be made to work on many kinds of voting machines. When San Francisco adopted IRV it screwed up and was unable to announce all nontrivial election results, supposedly for weeks; and now may have to abandon its counting machines entirely.
  4. Adopting IRV will cause voter errors ("spoiled" ballots) to become 7 times more frequent (based on San Francisco numbers). But adopting range voting appears to decrease errors.
  5. Range voting is monotonic, i.e. increasing your vote for somebody can help but cannot hurt them. IRV is not monotonic.
  6. In range voting, scoring your favorite candidate top cannot hurt either you or him. In IRV, it can hurt both.
  7. With IRV the "Nader spoiler" and "wasted vote" problems are not solved, contrary to pro-IRV-propaganda. Indeed, because of fear of these very effects, IRV voters tend to rank third-party candidates below top (even if favorite) and hence prevent their election, which presumably is why every IRV country is and always has been 2-party-dominated. For this reason IRV cannot attract support from intelligent third-party members.
  8. IRV makes ties and other nightmare-scenarios much more likely; Range voting makes them much less likely.
  9. IRV is historically more likely than range voting merely to lead to a backslide to plurality voting.
  10. IRV will (in plausible scenarios) elect candidate X in preference to candidate Y, even though based on the IRV votes, Y is pairwise-preferred over X (and over everybody else too) by an arbitrarily-huge supermajority of the voters. This happened in the Burlington 2009 mayoral election and appears to have happened in both the Peru 2006 presidential election (but less dramatically; merely a "55% majority" rather than a "huge supermajority" was thwarted) and the Chile 1970 presidential election (this time with about a 2:1 ratio supermajority being thwarted).
  11. See also our reports on the Ireland 1990 and Australia 2007 IRV elections and their pathologies. These were some of the most important IRV elections ever.
  12. Raising a candidate in your IRV vote from bottom to top-ranked can actually cause him to lose!
  13. Contrary to pro-IRV-propaganda, pathological IRV elections seem unpleasantly common in practice. (Theory: Pathology Survey. Real-world: e.g. see our surveys of the Louisiana governor and Australia House 2007 elections.) Two of the last five Debian elections would have exhibited pathologies had they been held using IRV.

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