Blake wrote: >So, is the point of your example that the Bush voter's are dishonest >then?
Dishonest? Is all strategic voting tantamount to dishonesty? If so, then I agree that the Bush voters are dishonest. If not, I see no reason to slander the (imaginary) Bush voters like that. Their choice to truncate their ballots strikes me as no more dishonest than a plurality voter casting a vote for the "lesser of two evils" rather than their true first choice. >Because if you just judge by the votes you give, without any >preconceptions about what Bush voters would really prefer, I think it >is obvious that Bush really does deserve to win in your example. My assumption, which seems reasonable given the left-right spectrum that most voters are comfortable placing themselves on, is that nearly all Bush voters would prefer Gore to Nader. If it pleases you, we can include this stipulation as part of my example. They choose not to rank Gore or Nader (in my example) because it cannot help them, but it can hurt them. I am arguing that, in this example, Ranked Pairs has created an incentive for truncation. >But as for the strategy argument, my response is as follows. Let's >imagine that some voters aren't aware that they are allowed to vote a >partial ranking. Then, they will have to randomly rank candidates >instead of placing them as equal. On average, these random votes will >tend to cancel each other out, with an effect as if they had voted in >margins. So in margins, knowing that they are allowed to vote partial >rankings doesn't give a new opportunity for strategy that did not >exist before. This is true... would-be truncators voting randomly will have the same effect as Ranked Pairs would predict otherwise. But is this a good rationale for using Ranked Pairs? The idea that one can truncate is not even remotely hard to grasp. It's no harder than the idea you can only vote for one candidate in plurality. Very few real-world voters will mistakenly fill out full preferences. Now, I think you're driving at a more subtle point here, that truncation actually makes a strategic difference in SSD, and blunting that difference makes the voting strategies simpler. My counter to this is that truncation also has a strategic impact in Ranked Pairs, as my example (with the attendant assumption about the true preference of the Bush voters) shows. It's true that the Bush voters could achieve the same effect by ranking their ballots randomly after Bush, but the coordination required to pull that off is dramatically harder to achieve. For all practical purposes, truncation has a strategic impact in both methods. >However, if you count ballots in a way that tends to penalize those >who vote partial rankings, which SSD does, I still haven't seen the example that shows this. I don't doubt that one exists, although I do doubt that the example will seem as likely as the one I provided. I could be wrong of course. >the voters would actually be better off believing that they aren't >allowed to vote partial rankings, since this will cause them to >randomly rank, and thereby avoid the penalty. In fact, an argument >can be made that this is true even counting with margins, but the >effect is minimized. I've shown an example here where truncation produced a BENEFIT, not a penalty, with margins. Furthermore, why shouldn't their be, in certain cases, some penalty to truncation? It basically means you're displaying less preferences -- you're voting less. It seems very natural that this could hurt you on occasion. The idea that more fully expressing your preferences can hurt you bothers me a lot more. >So, if people are better off believing that ranked ballots are not >allowed, why not just ban partial rankings? I mean, rather than allow >partial rankings, but covertly penalize them, why not just be up front >about it and say they aren't allowed? Well, if you force full ranking, then almost all the differences between Ranked Pairs and SSD dissolve. ALL the differences between Plain Condorcet and Ranked Pairs dissolve. So making this argument sort of defeats the purpose of arguing between Ranked Pairs and SSD in the first place. That said, I think that as a matter of voter freedom, we should not force the voter to fully rank the candidates. This makes voting far more of a chore in a place where a bunch of fringe candidates that the voter has not studied (nor does he/she care to study) make the ballot. This could make voting a very frustrating experience for many people. An election reform proposal that forces full ranking would also be hard to sell to the public. Finally, this could create some ugly strategies in a real election. In my example, for instance, the Republicans would want to ask their supporters to either vote random second places, or some other scheme designed to produce an even split. This hardly seems democratic, and the public reaction would be very negative. >Is it because you're hoping to >fool people who are trying to use strategy themselves? I'm not sure I follow this suggestion. There is strategic value to truncation in Ranked Pairs, and possibly SSD. You're going to have to explain to me the scenario where some people try to strategically truncate in SSD, only to be burned for it. -Adam
