Tim Hull wrote: > [...] > > I didn't even know there WAS a > multi-winner IRV as distinct from STV.
Actually, there are (at least) one or two, depending on how far you stretch the definition of single-winner IRV. Some local elections in Australia are counted like STV without surplus transfers (just successively eliminate defeated candidates). They call this "bottoms up". I'm told that it results in a little bit of proportionality but definitely not the same results as STV. And, unfortunately, the U.S. state of North Carolina recently came up with a multi-winner version of the contingent vote. This is just my own opinion, but I think it's actually worse than block voting because it eliminates the usefulness of bullet voting. They came up with it to replace multi-winner top-two (my name for it), in which 2 * S candidates advance to the second round, where S = number of seats. > [...] > > As far as STV > rules, I'm currently thinking standard fractional-transfer STV with > voters allowed as many rankings as there are open seats allowed. That > would limit rankings, but would keep the ballot the same as it is > currently [...] I think this materially affects the representativeness of STV results and should be avoided if humanly possible. It reintroduces spoilers and strategic voting -- at the slate/party level rather than the level of individual candidates. If I use all of my available rankings on the slate I most prefer, I am no longer able to help my second-choice slate defeat my last-choice one. Eventually, slates learn to run only as many candidates as they think will win (roughly the same problem as cumulative voting). I'm pretty sure this effect is larger in smaller constituencies with fewer seats to fill. (Can anyone help me clarify that point?) See below for more on constituency size. > Just to clarify the situation, there is somewhere in the > neighborhood of > 47 representatives on the Assembly. They are currently elected > in two elections (half in each of them) - the President is elected in > the Winter term one. The representatives are divided into > constituencies based on school/college. The largest such division has > 19 representatives, followed by 7 for the next largest, followed by a > 6-seat one, a 3-seat one, and several 1 and 2 seat ones. I'm not clear about the staggered terms. Are the 19 seats all filled at once, or are they filled 10 at one election and then 9 at the next? I agree with you about staggered terms in general (the interfere with STV), but 19 is a very large district magnitude for STV. I doubt that there's any agreement about the "best" upper bound on magnitude; I personally think it's about 9 or 11 seats. Is there any natural subdivision of the 19-seat constituency (e.g. East Campus vs. West Campus or Science vs. Humanities)? Otherwise you may actually need the staggered terms for that one school or college. My two cents, Bob Richard Publications Director Californians for Electoral Reform http://www.cfer.org P.O. Box 235 Kentfield, CA 94914-0235 (415) 256-9393 ---- election-methods mailing list - see http://electorama.com/em for list info
