<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On Jul 17, 2010, at 7:40 PM, Jameson Quinn wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">To clarify my position:<div><br></div><div>I think that, because of social dynamics which push voter groups towards symmetry (ie, B voters like A as much/little as A voters like B), honest condorcet cycles will be a fraction of what they would be in "impartial culture"-type models. Since such models usually give somewhere around 10% cycles, or a little more, I think honest cycles will be somewhere in the low single digits - 1%-4%. For this, I have little evidence, although it should be noted that Romania is not at all counter-evidence; one documented possibility in a large number of modern, polled elections is about what my proportion would have predicted. It is certainly not evidence against "most" cycles in a Condorcet system being due to truncation, as we have essentially 0 data on condorcet systems in public elections.</div></blockquote><div><br></div><div>Probability of honest cycles may vary between different societies and in time too. I also note that random vote models typically give more cycles than real world set-ups that may often have some fixed preference patterns, marginal parties etc.</div><div><br></div><div>I commented earlier that near ties and non geographic preferences may create cycles. Also symmetric preferences and geographic (distance based) models may often have cycles.</div><div><br></div><div>3) Let's assume that there are three voter/opinion groups that form a triangle. Then we will nominate the candidates - one candidate from each group. It may well happen that the candidate that group A nominates is more on the B side of that group than on the C side of that group. And the same for the two other groups. As a result a natural cycle is quite well possible. Voters of each group will rank the candidate of their own group first. With good probability they will rank second that candidate of one of the other groups that happens to be close to one's own group.</div><br><blockquote type="cite"> <div><br></div><div>I think that the necessary conditions for truncation/burial to be a rational strategy will be much more common. It depends a lot on the average number of "serious" candidates per election, but assuming that with a Condorcet method that number would be somewhere between 2.5 and 5, with a minimum of 2... well, I don't want to pretend I've done the calculations, but my guess is that that would lead to somewhere between 20% to 60% of elections having a rational truncation which would affect the result. I'd imagine that a possible truncation would actually happen somewhere from 25% to 75% of the time. So honest cycles should be roughly 1%-4%, and truncated ones roughly 5%-45%. If these broad ranges are right, then truncated cycles will be 55%-98% of all cycles - probably 66%-90% - ie, "most". </div> <div><br></div><div>This is why I think that system performance relating to truncation strategy is at least as important as honest performance, at least for decent systems where the differences between honest performance are not too large.</div></blockquote><div><br></div><div>I first note that also strategic behaviour may vary greatly between different societies, partly because the political opinion space is different, but maybe more importantly because the morale and rules of behaviour of the society. In some societies people would enjoy use of all kind of more or less working strategic tricks while in others the whole idea of trying to cheat (e.g. crate an artificial loop) would be considered unacceptable (and any candidate that would recommend that would soon lose lots of support).</div><div><br></div><div>In Condorcet rational strategic voting is not easy. It is possible that after the election one can see that some well coordinated group of voters could have changed the result (assuming that other voters would all have voted sincerely). But this is still quite far from having a rational strategy available to the voters at the election day. I have asked people to write down rules that could be used in any Condorcet elections or in some particular Condorcet election. But I have not seen any such descriptions yet. Are there some clear rules that would make strategic voting rational in some elections? In typical elections (large, public, with independent voters and changing opinions) there are many problems like inability to coordinate the behaviour of the intended strategic voters, unwillingness of some to participate in the strategy, other possible strategies, changing opinions and variation in polls, optimistic people that believe in some nice outcome, too difficult strategic guidance that people will not follow, risk of backfiring strategies, voters voting against / not supporting groups that try to "cheat" etc.</div><div><br></div><div>So, my claim is that in typical elections most often sincere voting is the best strategy. In countries where people are used to vote as told by their own party strategists (e.g. Australia) the probability of rational strategic voting is somewhat bigger. But in both cases I'd like to see first scenarios and _rational_ guidance to the voters that would work also in real life, not just on paper. I.e. guidance like "if opinion polls show that ... then vote so that ..." or "since opinion polls show that ... you should vote so that ...". Are there such cases? Are they common? Is it rational to say to the voters of Condorcet elections "just vote sincerely, that's the best strategy"?</div><div><br></div><div>Juho</div><div><br></div><div><br></div><br><blockquote type="cite"> <div><br></div><div>JQ<br><div class="gmail_quote">2010/7/14 Warren Smith <span dir="ltr"><<a href="mailto:warren.wds@gmail.com">warren.wds@gmail.com</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"> > I believe that Jameson Quinn is right when he says that most Condorcet cycles are probably artificial,<br> i.e. they are caused by strategic truncation or strategic burial.<br> <br> --For a real life example of a Condorcet cycle in a large national election, see<br> <a href="http://rangevoting.org/Romania2009.html" target="_blank">http://rangevoting.org/Romania2009.html</a><br> Contrary to Simmons' conjecture/intuition, this cycle seems to have<br> been not "strategic," it was "honest" -- because the evidence for the<br> cycle consists of pairwise-poll data, and there is no motivation for<br> dishonesty in 2-man pairwise polls.<br> <br> Further, other real-world cycle examples (?) are noted, discussed 2nd<br> half of section 4.<br> <font color="#888888"><br> --<br> Warren D. Smith<br> <a href="http://RangeVoting.org" target="_blank">http://RangeVoting.org</a> <-- add your endorsement (by clicking<br> "endorse" as 1st step)<br> and<br> <a href="http://math.temple.edu/~wds/homepage/works.html" target="_blank">math.temple.edu/~wds/homepage/works.html</a><br> </font><div><div></div><div class="h5">----<br> Election-Methods mailing list - see <a href="http://electorama.com/em" target="_blank">http://electorama.com/em</a> for list info<br> </div></div></blockquote></div><br></div> ----<br>Election-Methods mailing list - see <a href="http://electorama.com/em">http://electorama.com/em</a> for list info<br></blockquote></div><br></body></html>