Wait, not IRV, umm, that other thing...

[dougo]

In the past I've mentioned Instant Runoff Voting (IRV) as a way to fix the totally broken voting situation that's led to "lesser of two evils" contests for as long as I've been a voter. Well, thanks to a link in novalis's journal, I am reminded that IRV is rather broken itself. I had looked into this a while ago, but forgotten the details; the Election Methods Education and Research Group (EMERG) has a good collection of information, as does Wikipedia. The first thing to know is that Arrow's impossibility theorem proves that no voting system is perfect, which is almost as depressing as Gödel's incompleteness theorem. Fortunately there is somewhat of a loophole, in that if you relax the definition of "perfect" a little bit, there are some voting systems that satisfy all reasonable criteria; in particular, the EMERG advocates a form of Condorcet voting. However, the Center for Voting and Democracy (CVD) (who advocates IRV) has its own complaints about Condorcet (and other alternatives). Oh dear, just when it seems like the media (e.g. The Nation) might finally be getting the message that plurality voting sucks, there's some serious dissent about which alternative is best. I'm currently more swayed by EMERG's arguments towards Condorcet than by CVD's arguments against it, though I need to do some more reading, but I'm really afraid that this kind of confusion may mean we're stuck with plurality voting (and the corrupt two-party system it engenders) for the forseeable future. Bah!

Comments

[dougo.livejournal.com]

I'm uncomfortable with approval voting; it doesn't capture the fact that I prefer A to B, but also prefer B to C. Either I vote solely for A, in which case it's the same as a plurality vote, or I vote for A and B both, in which case I'm hurting A's chances if it's a close vote—same problem as IRV. Even if I vote naively, just following the instructions: do I find B acceptable? Well, I dunno... relative to C, sure, but I'm not really sure what that means as an absolute measure. I might not even consider A to be acceptable, so maybe I should just leave the ballot blank!

[mrmorse.livejournal.com]

I found a page about approval voting while poking around at Wikipedia. It makes the claim that if everyone follows a "good" voting strategy, then approval voting will give the same result as Condorcet voting.

It also has a response to your problem. The fear is that approval voting will tend to result in compromise candidates being elected. Consider an election between Kucinich, Lieberman, and Bush. If most supporters of Kucinich or Bush also vote for Lieberman on the basis that Lieberman is at least better than the third candidate, then Lieberman will win, which may not be the desired outcome.

The claim is that IRV is actually more likely to produce this result than approval voting. In IRV voting, Kucinich voters are likely to vote 1. Kucinich 2. Lieberman 3. Bush, which may actually overstate their approval of Lieberman. If Kucinich gets the fewest votes, his votes will be kicked over to Lieberman, resulting in Lieberman winning. Kucinich voters may be unhappy with this outcome.

In approval voting, Kucinich supporters may be more likely to vote only for Kucinich, therefore not supporting the compromise candidate. This is equivalent to voting for Kucinich first in IRV and leaving the other slots blank, but a study has shown that voters are less likely to throw additional support to compromise candidates in approval voting than in IRV, making it less likely that a compromise candidate will be elected.

This year's Democratic primary offers a practical example of the benefits of approval voting. I personally thought that several of the candidates would be good Presidents, while others would not. Furthermore, of the candidates I supported, I was fairly indifferent as to which one got nominated. (The differences between Kerry and Edwards are negligible, and I don't think Dean or Clark were that far off.) Under the current voting system, I could only choose one. I felt unsatisfied about the choice I made and have been questioning it since. Under IRV, I would be able to rank the candidates, but that wouldn't really capture the sharp difference I feel between the good candidates and the bad candidates while it would exaggerate the differences between the good candidates. Under approval voting, I could have voted for all of the candidates I liked and feel confident that I was increasing the likelihood of any of them winning.