Dave Ketchum wrote:
On Fri, 12 Nov 2004 10:11:03 -0500 (EST) Warren Schudy wrote: Subject: Re: [EM] IRV in San Francisco
1) Did the ballot only allow each voter to give the top three choices? I suspect that restriction would significantly decrease the effectiveness of IRV.
Agreed a decrease, but I question its being significant: Vote your true preference. Vote your preference among those likely to win.
Most of the time that is all that is important, and being able to vote a third choice covers most of the exceptions.
It depends on the election. In a partisan scenario, or when few candidates are likely to run, three choices are probably as good as a hundred. But in some SF districts, candidate fields of 15+ are not uncommon (district 5 had 22 candidates). And in non-partisan elections, it's not necessarily known which candidates are likely to win.
Of course IRV declines rapidly in effectiveness as the number of candidates increases, even if full ranking is allowed. But at least then it would compare favorably to a separate top-two runoff election.
Bart ---- Election-methods mailing list - see http://electorama.com/em for list info
