It really depends. Real-world data suggests that it could be more common than that for partisan elections, and (much) less-common for primaries or nonpartisan elections.
JQ 2011/11/1 David L Wetzell <wetze...@gmail.com> > Not as much if there are only 3 candidates, according to Stephen Brams, a > mathematician determined that in a close 3-way election with only 3 > candidates that the odds of non-monotonicity mattering would be 20%. > That's still 4-1 in favor of it not mattering and close 3-way elections > are not common. > > dlw > > > On Mon, Oct 31, 2011 at 7:51 PM, Jameson Quinn <jameson.qu...@gmail.com>wrote: > >> >> >> 2011/10/31 David L Wetzell <wetze...@gmail.com> >> >>> >>> >>> On Mon, Oct 31, 2011 at 5:59 PM, Andy Jennings < >>> electi...@jenningsstory.com> wrote: >>> >>>> David, >>>> >>>> My strongest feeling about your recently proposed system is that the >>>> "three" is so arbitrary. >>>> >>>> What if there are eight candidates running, and I really like five of >>>> them? Then approving three might not be enough. >>>> >>> >>> Most people aren't as politically keen as you are. We need to design >>> rules for the typical voter, not ourselves. I think the number of >>> contested seats plus two is a good rule of thumb... >>> >>> >>>> I know you said that real elections only seem to have four strong >>>> candidates, but the current republican primary seems to have at least seven >>>> totally legitimate candidates in the race. >>>> >>> >>> define totally legit? From a wonk perspective or a hack perspective? >>> There's three realistic candidates right now, and a bunch of me >>> threes/fours/what-nots >>> . >>> >>>> Both 2008 primaries were the same way. Sure, the press is constantly >>>> trying to whittle it down to about four. But why should we let the press >>>> do the whittling? Shouldn't that be done by the voting system in some way? >>>> Should we use a different system for these larger elections? >>>> >>> >>> dlw: It's not just a media thing, it's also a matter of cost-benefit >>> analysis. When there's only one winner, it just isn't cost-effective for >>> there to be lots and lots of candidates. >>> >>> My point is based on reality as it is, not as I'd like it to be. We >>> need to gear our reforms to reality, not our wishful thinking about how >>> elections ought to be... >>> >>>> >>>> If there are only three candidates running, then the AV step does >>>> nothing. If there are four candidates running, then the AV step is really >>>> anti-plurality. >>>> >>> >>> dlw: I'm saying that there can be more than three or four candidates on >>> the ballot, but there tends to be 3 or 4 serious candidates by virtue of >>> economics of elections. .. >>> >>>> >>>> And as Kathy pointed out, you'd still better tell people that it's not >>>> safe to put their favorite first. >>>> >>> >>> dlw: That'd be silly. If you do the math, while it's possible that >>> there could be a non-monotonicity problem in the unlikely event of a close >>> three way election, it's still less likely than the more typical outcome >>> where it makes sense to vote your preferences. And so long as the odds >>> favor the typical outcome, the possibility of a sour grapes situation are >>> not consequential. It does not rationally change voter behavior. >>> >> >> In nonpartisan/monopartisan elections, including party primaries, there >> is unlikely to be a nonmonotonicity problem. In partisan elections where >> more-or-less one-dimensional spectra are the norm, nonmonotonicity is a >> very real threat. >> >> JQ >> > >
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