Australia's 2007 elections (executive summary)

IRV advocate Rob Richie recently hailed the Australian house elections (held 24 November 2007) as a "big success" for Instant Runoff Voting (IRV). These elections threw out both Prime Minister John W. Howard and his party, the NatLibs, enthroning Kevin Rudd and giving his Labor Party majority control.

But was this really a big success for IRV? We examined that using data from the Australian Electoral Commission web site. (Warning: All this is based on data we got from the AEC on 30 November 2006, and it is not in final form and may change slightly as, e.g. they count more absentee votes, recount, etc. That will not affect our conclusions much if at all.) The conclusions of that examination are as follows:

  1. If Australian house elections had been held with plain plurality voting rather than IRV then (assuming every voter would have voted for the same candidate they top-ranked with IRV) the results of 8 of the 150 House races would have changed. In all 8 cases, plurality voting would have elected the NatLib candidate instead of the Labor candidate who actually won with IRV. More realistically, with plurality probably some third-party voters would have been more-afraid to vote third party and would have voted for the top-two party candidates. If so, then fewer than "8" races would alter (perhaps only 6 or 7). That would decrease the importance of IRV in one way (fewer results changed) but in another sense (improved voter honesty) would increase it back.
  2. Labor and Rudd still would have won majority control with plain plurality voting, just a smaller majority (77 out of 150 seats, versus what they got with IRV, which was 85 out of 150).
  3. In view of this, we agree with Rob Richie that these elections were a "big success," or at least a "success," for IRV. But approval and range voting would have been an even bigger success as we'll now explain.
  4. If Australia had employed approval, range, or Condorcet voting instead of IRV, then we believe the same result would have happened, i.e. exactly the same 8 races would have swung toward Labor. (Perhaps only 6 or 7 with range and approval if the third-party voters did not approve Labor enough or score it highly enough, but if so then range & approval would arguably have made a better call than IRV.)
  5. All 8 IRV-swinging races displayed a pathology called "participation failure" or "no-show paradox." That is, in every case, adding some number of extra Green>Labor>NatLib voters, would have caused the IRV winner to become NatLib. That is bad, because:
    1. These extra voters, by voting honestly, would have made the election result worse in their view.
    2. They would have been better off not voting at all (as, in fact, they didn't).
    3. They also would have been better off voting dishonestly; and with these extra Green voters, some of the Labor voters also would have been better off voting dishonestly.
    4. All 8 losing Natlib candidates have the following valid gripe, enabling them to attack the legitimacy of IRV:
      1. I lost to Labor with IRV,
      2. But if extra voters, all of whom ranked me dead last and preferred Labor over me, entered the picture, then I would have won,
      3. So, since I would have won and defeated Labor even with this handicap, why the heck did I lose without the handicap?
        ∴ My defeat was bogus or the election system (IRV) is bogus, or both.
  6. Approval and Range did not exhibit any such pathology, hence no candidate in any of the 150 races would have had any such valid gripe enabling attacking the legitimacy of range & approval voting.
  7. The myth that IRV pathologies are "extremely rare" is totally refuted. The claim that IRV improved on plain plurality voting is undermined because the two systems delivered exactly the same winners in every case, except for cases in which the legitimacy of IRV can validly be questioned.
  8. Voters might have wanted to get rid of Howard and install Rudd because they disliked the Iraq War. That's fine, but maybe they did not like the pill they then were forced to swallow of implicitly endorsing Rudd's semi-Socialist economic views. The difficulty here for such a voter is that since IRV leads to 2-party-domination (Australia's 2007 House contains zero third-party members) she has no choice besides Rudd & Howard. If Australia had a voting system that did not lead to 2-party domination, she could have more credible choices – e.g. perhaps there would be an antiwar and anti-Socialist choice. That's an advantage for approval and especially range voting, versus IRV.
  9. Australia is still counting and recounting all the close IRV elections 1 week later and warn that it is not clear that Labor really has 85 seats, etc (those results are subject to change). That is because IRV is a difficult system to count, and ties and near-ties even between "no hoper" candidates, can change the winner. Australia's numbers of invalid "spoiled" ballots were easily sufficient to change the winner in many of the 150 races. (And, incidentally, spoilage rates are lower with range and approval voting.) Approval (or even range) voting are simpler to count and less subject to tie-crises. They would have been counted sooner with fewer worries, less effort, and less cost.

Detailed look

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