James Green-Armytage suggested: > Let's try to follow through with one of these examples > until the end. Let's say that in a presidential election, the > ballots cast are > > 48: Bush > McCain > Gore > 3: McCain > Bush > Gore > 49: Gore > McCain > Bush > > The Condorcet winner is McCain, and the IRV winner is Bush. > Now, let's imagine that there is a runoff election > between McCain and Bush. How do you think that people will vote?
1. I cannot usefully comment of the likely outcome of this run-off because I don't know enough about the candidates and the electors. 2. More importantly, changing to a run-off election part-way through and asking questions about that, does not address the issues arising from the outcome of the Condorcet election. My hypothesis is that politicians and the general public are likely to reject both the election result and the voting system if the voting system allows the "weak middle" to come through and win when that "weak middle" has the first-preference support of only a very small percentage of the voters. They understand very well all the ideas of "compromise" and "everyone's second choice", but based on their response on some other "dimension", they will reject the result and the voting system that produced it. Trying to guess and analyse what these voters might do in various run-off sub-sets doesn't really help us to measure their likely response on this "other dimension", except that there is good evidence that voters (at least some voters) will vote different in an exhaustive ballot (repeated run-off) from how they would vote if IRV were used. Some analysts see that difference as a good feature of the exhaustive ballot, others see it as a bad feature. I have in mind here the voting behaviour of MPs of certain UK political parties who have, in the past, elected their party leaders by exhaustive ballot. The results from successive stages have shown very clearly that these voters have changed their "preferences" quite markedly after they have seen the preferences of all the other voters in the previous stage and stages. In this particular case there may be a strong element of wanting to be seen to have been "on the winning side" (even when the ballot is secret) because that is the path to political preferment (high office at the leader's sole discretion). However, I suspect this is a more general phenomenon. Problem is, we very rarely get relevant data because no one normally asks real electors to vote the same real election by several different systems. James G. ---- Election-methods mailing list - see http://electorama.com/em for list info
