On Jan 10, 2010, at 1:02 PM, Abd ul-Rahman Lomax wrote: > At 01:06 AM 1/10/2010, Jonathan Lundell wrote: >> On Jan 9, 2010, at 9:23 PM, Abd ul-Rahman Lomax wrote: >> >> > On the other hand, in one-third of nonpartisan top-two runoff elections, >> > which IRV supposedly simulates, the runner-up in the primary goes on to >> > win the runoff, a "comeback election," according to a FairVote study. It >> > simply does not happen with IRV. >> >> It's hard to know what to make of this claim, other than, "so what?" -- if >> what you're comparing to TTR is the IRV candidates with the highest >> first-choice ballots. > > I'm comparing *elections*. Yes, not all questions are addressed, but the > response of "so what?" misses the point, obviously. If we assume sincere > voting in TTR
I would not. TTR encourages favorite betrayal for much the same reason FPTP does. > and IRV, and if we consider real world conditions (separate runoff, not > merely some simulated runoff with the same voters and the same preferences > and no new knowledge or shift of preference or better consideration, etc.), > the results are quite different. That preference order doesn't shift in > nonpartisan IRV elections, though the vote transfer process, was completely > unanticipated, as far as I know. Mr. Lundell, were you aware of it? Did > anyone predict this? > > What this means that, with very little exception, you can use Plurality > instead of IRV. Again, I would not make that assumption. In this case, not simply because of the difference in voter behavior and voting rule, but because the nominating incentives are radically different. > And this just may explain why Plurality has remained so popular for so long. > In certain contexts, it works quite well. > >> Presumably voters in TTR and IRV elections know the counting rules. > > No. We can't presume that, in fact. Both TTR and IRV generally encourage > sincere first-preference votes, not in reality, but in appearance. I believe > that most votes in the current IRV elections in the U.S. are quite sincere, > they aren't being gamed, as they would need to be to maximize voter expected > satisfaction, in some cases. With TTR, indeed, voters may know the rules. > They might even know IRV rules, but the *implications* of the rules, that > knowledge, from what I've seen, is unusual. > >> The meaning of a first-choice IRV vote is not the same as a TTR first-round >> vote. One plausible interpretation: if a TTR primary results in A>B, A tends >> to have all the votes A is ever going to get, but B, in the runoff, gets all >> the "anybody but A" votes, and wins. > > When there is a runoff between two candidates, there is much closer > examination of the two candidates. Further, preference strength enters into > runoffs, causing results to shift toward what would be range voting results. > Sincere range voting! I'm assuming, here, that the runoff is a special > election. If the primary is the special election (seems to be common in North > Carolina, for example), then it is the primary results that are > range-shifted. That's improved election quality, Johathan. People vote when > they care. We cannot tell from low turnout if the turnout is low because > voters are equally disgusted with both candidates, equally pleased, or truly > don't care about who wins no matter who the candidates are. High > participation in a general election means a lot of noise, voters with low > preference strength (which may be due to lack of knowledge, or may be > intrinsic, i.e., they *do* know the candidates and don't care which one wins). > > The proposed explanation for comeback elections, however, "anybody but A," is > probably rare. Much more likely is this, as one example: > > B is a dark horse, wasn't expected to do as well as actually happened. When B > makes it into the runoff, suddenly those who supported B or who would have > supported be had they known about B, will turn out to vote. In the other > direction, those who voted in the primary and who actually have low > preference between A and B may not turn out to vote; perhaps A was better > known and got votes from these voters. So A may lose votes and B may gain > them. Add to this the effect of additional campaigning, where B, now being a > serious contender, gains more funding and more explicit support, perhaps the > recommendation of other candidates. > > Whether or not all this is likely may depend on the margin, but if B was > truly a dark horse, B stands to gain votes from those who voted for other > candidates. To me, the really interesting situation is where a center > squeezed candidate doesn't make it into the runoff. What were the vote > margins? Are there signs that the eliminated candidate was actually the > Condorcet winner? By what margin and what preference strength? These would be > factors in determining if a write-in campaign is appropriate. Using an > advanced method in the runoff, even if there are only two candidates on the > ballot, and allowing write-ins, allows fixing this problem with top two > runoff! And the problem is less likely to arise if an advanced method is used > in the primary as well. > > >> OTOH, A>B>... in the first round of an IRV election tells us considerably >> less, since the cost of voting for a non-poll-leader is considerably less >> than with TTR. It's entirely plausible, though of course not necessary, that >> the A:B first choice breakdown reflects the lower-choice breakdown of the >> other voters. > > This is what we see in IRV elections, when they are nonpartisan. It is as if > the supporters of each candidate as most-preferred are a sample from the same > population that is otherwise similar. So if, say, those who prefer someone > other than A are considered as to their preference for B>C, the ratio of B>C > preferences will be the same for those who prefer A. This was unexpected, to > me, but it does make some kind of sense. > > Most of our thinking about voting systems has been colored by thinking in > terms of factional preferences, which are roughly predictable and not at all > like this. We expect that a Progressive voter in Burlington will be more > likely to support the Democrat over the Republican, and by significant > margins, and we likewise expect that a Republican voter will be more likely > to prefer the Democrat over the Progressive. In Burlington, the Democrats are > in the middle, the center, they are the local moderates. > > But nonpartisan elections don't seem to work like this. They are about > personalities, less about issues and general stances on issues, I suspect. > They may be about perception of trustworthiness. ---- Election-Methods mailing list - see http://electorama.com/em for list info
