<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On May 25, 2010, at 1:20 PM, Jameson Quinn wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">What are the worst aspects of each major voting system?</blockquote><div><br></div>Runoffs need avoiding, due to their expense.</div><div> Plurality needs them when lacking a majority, for we know they could not completely express their wants - and still have trouble.</div><div> For others, need thought as to when they are worth the pain.</div><div><br></div><div>Primaries are another Plurality need - need thought as to when they are worth their expense elsewhere - and how to do them well.</div><div><br></div><div>Write-ins - needed, though need should be avoided at Runoff time.<br><blockquote type="cite"><div><br></div><div>-Plurality: Everything. It routinely requires dishonest strategy from a large minority, or even a majority, of voters. Enough said.</div></blockquote><div><br></div>Does not let me express my desires - unless bullet voting was always good enough for all.<br><blockquote type="cite"><div><br> </div><div>-IRV: Voting can hurt you (nonmonotonicity). That means that small third parties can survive, but once they threaten to pass 25%, you're back to the problems of plurality. A great learning tool to understand this is <a href="http://zesty.ca/voting/voteline/">http://zesty.ca/voting/voteline/</a> , which lets you play with one-dimensional scenarios and see how common nonmonotonicity is.</div></blockquote><div><br></div>Ballot is good, but counting too often ignores what is important.<br><blockquote type="cite"> <div><br></div><div>-Condorcet: complexity. While the basic idea of one-on-one matches is simple, the details of tiebreakers are enough to make most voters' eyes glaze over. Moreover, the need to individually rank numerous candidates is more work than many are ready for, and the inevitable shortcuts they'll take could harm results.</div></blockquote><div><br></div>Ballot is good - rank only the candidates you like best, with best at top and equal ranking permitted. Bullet voting is fine when that is your liking. </div><div><br></div><div>Some talk of voting for frontrunners - above sentence gives all the encouragement worth offering.</div><div><br></div><div>Its ballot is like IRV's - it is the counting that is more complete and smarter. </div><div><br></div><div>The counting, reportable as an N*N matrix comparing each pair of candidates, is valuable both to indicate progress and to help in deciding how to do better.</div><div><br></div><div>Tiebreaking is only a problem if you feel you need, but cannot get, adequate understanding. It is simply a cycle of those most voted for, thus including the winner, separated from the less-liked rejects.<br><blockquote type="cite"> <div><br></div><div>-Approval: divisiveness. By forcing all votes into an all-or-nothing mold, it does not allow partial alliances between candidates. Consider the probable results in the recent Hawaii election, where the majority democrats split their votes between two candidates, leading to a Republican win. Lets assume for a second that, because the two democrats were distinguished mainly by individual not ideological factors, cross-party approvals are insignificant; and that Democrats are pretty evenly split between the two choices. Then, there are two possible results: either the less-cooperative Democratic faction wins, or, if the "uncooperative arms race" gets out-of-hand, the condorcet-loser Republican wins. In other words, the system has incentives not to cooperate between two frontrunners running approximately even in the polls, no matter how close they are, and these incentives are unhealthy whether or not they get out-of-hand.</div></blockquote><div><br></div>This sits between Plurality, which supports only bullet voting, and Condorcet that provides for needed ranking of multiple candidates.<br><blockquote type="cite"> <div><br></div><div>-Range: Strategy is too powerful. If one faction is more inclined to honestly rank, seeing themselves as neutral judges, while another faction has selfish reasons to strategically vote approval-style, the strategic faction will dominate, even if they are a minority. Range is very robust under strategy, if it's not factionally biased; but too vulnerable to factionally biased strategy. You can rationalize until you're blue in the face about how minority Range winners reflect a true societal preference; but imagine how you'd feel if Bush/Gore/Nader had been decided for your least-favorite against the will of the majority, due partly to a certain complicity of some people who should should SHOULD have been on your side, and partly to the obvious and dishonest machinations of the winning side, and you'll see that this is still a real problem. (OK, I know that doesn't take a lot of imagination for some people.)</div></blockquote><div><br></div>The rating is a great ability, but trying to do it well is a major pain.<br><blockquote type="cite"> <div><br></div><div>-Bucklin: Bucklin (with equal rankings, of course) doesn't really have a single biggest weakness. It is still technically just as vulnerable to divisiveness as approval; but the trappings tend to hide this fact, and so it shouldn't be as much of a problem in practice. Still, it doesn't have any really strong points either. It's not the best honest system like Range; it doesn't give a Condorcet guarantee; and it's more complex than Approval, without really fixing Approval's greatest flaw.</div></blockquote><div><br></div>In a way, more complex than Condorcet, with Bucklin's complications not worth the pain.<br><blockquote type="cite"> <div><br></div><div>So, allow me to restate my favored single-winner system, which, I think, avoids all of the major pitfalls above. I call it Approval Preferential Voting (the acronym, APV, is I believe only taken by American Preferential Voting, an old name for Bucklin; and since this system could be considered a Bucklin variant, I think that's just fine.)</div> <div><br></div><div>Voters rank each candidate as preferred, approved, or unapproved. If any candidates have a majority ranking them at-least-approved, then the one of those which is most preferred wins outright. If not, then the two candidates which are most preferred against all others (ie, the two Condorcet winners based on these simple ballots, or the two most-preferred in case of a Condorcet tie) proceed to a runoff.</div></blockquote><div><br></div>How do voters get to a similar measure of whether a candidate rates as approved?<br><blockquote type="cite"> <div><br></div><div>(As a ballot mechanic, parties as well as candidates could be ranked, and any candidate not specifically ranked would default to her party's ranking.)</div><div><br></div><div>This method is very simple. I think that the description above, without the parentheses, is simple and intuitive; it uses only concrete terms. It is also very easy for a voter to sort candidates into three rankings; I'd argue that this is the easiest possible ballot task, easier in general than either two or four ranking categories. (Two means too many compromises, and four means too many fine distinctions.)</div></blockquote><div><br></div>I understand ranking, as done for Condorcet, as doable since it is based on he voter's own evaluation. I then wonder how to fit to categories such as the above.<br><blockquote type="cite"> <div><br></div><div>It's not quite the same as MCA or any other Bucklin system, since if there are two approval majorities, the preferences, not the approvals, break the tie. This makes APV more lesser-no-harm-like than Bucklin, encouraging voters not to truncate.</div> <div><br></div><div>Note that APV is still not a lesser-no-harm method. But it is in some sense a lesser-minimum-harm method; extra approvals cannot hurt your candidates chances for an outright win OR for a win if there's a runoff, the only way they can hurt is the unlikely situation where they are pivotal in preventing a runoff. I think that this minimizes the divisiveness I discussed with Range above; for instance, in Hawaii, I'm sure the two democratic factions would have had little trouble giving each other sufficient honest approval for the strongest one to win outright.</div> <div><br></div><div>Also, if there is no runoff, this method "violates Arrow's theorem". That is, because it does not use a preferential ballot (and thus doesn't have "unlimited domain" by Arrow's terms), it satisfies some Arrow-compatible definitions of the Majority Criterion and Independence of Irrelevant Alternatives Criterion (including clones). (APV as a whole does violates both those criteria, but I'd argue that this would be unlikely in practice.)</div> <div><br></div><div>This system as a whole is monotonic (unlike most two-round systems). Raising a candidate X can only help X win if there are already one or more candidates with majority first-round approval; it can only avoid a runoff if thereby X wins; it cannot knock X out of the runoff; it cannot knock a weaker opponent out of the runoff (this is the step where many two-round systems fail); and it obviously helps in the runoff itself against any given opponent.</div> <div><br></div><div>It does technically fail the participation criterion; your vote could knock your second-favorite candidate out of the runoff, thus causing your favorite to lose to a worse candidate in the runoff. However, this is pretty implausible, since, in order to knock out your second-favorite, your favorite must demonstrate that he's stronger than her in a Condorcet sense, which would strongly suggest that he's more likely to win a runoff than her. (Even in the extremely-rare cases where this wasn't true, it would be almost impossible to know that was so based on polling; so this failure is a very implausible basis for any strategy in any event.)</div> <div><br></div><div>The worst downside of this method that I can see is that, unlike the voters, the leading candidates have little motivation (except reciprocation) to express approval for other candidates. Negative ads could still be the order of the day. But you can't solve everything.</div> <div><br></div><div>I've advocated for the different aspects of APV before, but I haven't presented (or named) it as a whole. I'd appreciate any comments. Honestly, I think this should be the simple, practical reform we're all pushing for, even as we argue and develop more-complex systems with better theoretical properties.</div> <div><br></div><div>JQ</div></blockquote></div></body></html>