2012/2/4 Bryan Mills <bmi...@alumni.cmu.edu> > > From: Bryan Mills <bmi...@alumni.cmu.edu> >> > To: David L Wetzell <wetze...@gmail.com> >> > > If there are 3-5 seats STV then the number of candidates won't >> > proliferate >> > > too much and there'd be 5-7 places to vote. This would keep things >> > > reasonable. >> > >> > To get reasonable proportionality with only 3-5 seats per district >> > you'd probably need to go to an MMP system, with all its added >> > complexity. Otherwise Droop proportionality doesn't buy you much over >> > FPTP; with 5 seats the Droop quota measures to a precision of ~17%, >> > and the remaining 17% in each district is still susceptible to >> > gerrymandering. >> > >> >> Not much? >> The goal here is not perfectionism wrt proportionality. >> The goal is to increase proportionality and to increase the number of >> competitive seats >> and to reduce the cut-throat competitive nature of US political rivalry >> between its two biggest parties >> so they can't dominate the other and have more incentives thereby to work >> together on the many issues that need work. >> > > I'm doubtful that 3-5 candidate districts actually would "increase the > number of competitive seats". Each major party ends up with 1-2 safe > seats, and at that level of granularity gerrymandering and geographical > polarization are still significant enough to render the last seat > non-competitive in most districts. (It would increase proportionality > somewhat - by transforming some of the safe-by-gerrymandering seats into > safe-by-Droop-proportionality seats - but you seem to be arguing that > proportionality isn't as important as competition.) > > Suppose we have two parties with a 50/50 split and 5 seats per district, > with one party more popular in urban areas and one more popular in rural > areas. And suppose that the district lines are drawn such that 4/5 of > districts are slightly more rural than average and 1/5 of districts are > more urban than average, so that the 5th seat in each district becomes > relatively safe as well. (We can do this fairly easily using geographical > boundaries by centering 1/5 of the districts around cities.) > > Scale that up to 400 legislators (80 districts). What do we end up with? > 320 "natural" safe seats guaranteed by Droop proportionality (160 for each > party) > 80 gerrymandered-safe seats for the rural party > 20 gerrymandered-safe seats for the urban party >
First, your numbers add up to 420. I think you meant 64/16 for the safe seats, which is only a 56/44 advantage, not 60/40. Note that the "safe" seats would still swing if there were a swing in national mood of around something less than 8%, not something less than 25% as in single-member districts. And the more highly-gerrymandered the map is, the tighter that margin, and so the greater the chances of it backfiring against the gerrymandering party. Gerrymandering is a fine art, but 8% doesn't leave a whole lot of room to play with. Considering safety margins and misfires, I doubt that the gerrymandering party could get anything close to the 6% representation advantage your (corrected) numbers suggest. So, while 2-3% unfairness is still a problem, I think it's a big step up from where we are. > > Now, despite a 50/50 natural split, the rural party has a 60% > supermajority. And, of course, if you draw the district lines differently > you can do the same thing for the urban party. > > So there's still relatively little hope that a system with such small > districts would produce a party-proportional legislature. As you point out > elsewhere, it might still be possible to get an ideologically-proportional > legislature if you can get the parties themselves to shift ideologies. > > > > If you assume two major parties with ~40% of the electorate each, that >> > means that the 5th seat in each district is noisy -- but it's not >> > random noise, it's systematically biased by the parties' voting >> > strategies and the choice of district boundaries. Larger districts >> > allow finer-grained Droop quotas and thereby reduce that noise. >> >> dlw: Smaller districts engender less opposition from those in power. >> They keep the constituent-legislator relationship more so. >> > > Absolutely agreed that smaller districts engender less opposition from > those in power. That's because smaller districts don't fix the biases that > keep them in power. > > They do maintain the constituent-legislator relationship, *for the subset > of voters who voted in favor of the legislator*. For the remaining Droop > quota of un- or under-represented constituents the nonexistence of the > constituent-legislator relationship is also maintained. > Here's my chance to plug PAL representation<http://wiki.electorama.com/wiki/PAL_representation>, which does PR but uses existing-sized districts and preserves a specific constituent-legislator relationship for all but (up to) one Droop quota of voters. > > > > >> But if we assume that partial rankings are effective, there's still >> the >> > >> strategy/computation tradeoff to deal with: allowing truncated >> ballots >> > >> still doesn't help with favorite-betrayal, and STV variants less >> > >> susceptible to favorite-betrayal are also less susceptible to >> efficient >> > >> counting. >> > >> >> > > >> > > dlw: Truncated ballots may not end favorite betrayal, but it'll help >> with >> > > it. >> > >> > I don't see how; please elaborate. >> > >> >> This is essentially the same arg that IRV does not end the fact that some >> will still on occasion be pressured to betray their favorite. >> But it'll be of less consequence when it happens. It won't be 3rd party >> dissenters, it'll be the supporters of a major party that does >> not position itself near the true political center who get pressured to >> betray their favorite and that in turn will pressure the major party >> to adapt or die. >> > > Are you saying that favorite-betrayal isn't a problem when those forced to > do it belong to a major party? I hope I'm just misunderstanding your > point, but it sounds to me like you're describing a system like FPTP but > with major-party spoilers substituted for minor-party spoilers. > > > > >> With an implicit "first-preference" approval, it has the same problem >> as >> > >> traditional STV (i.e. IRV), namely of unduly rewarding >> > favorite-betrayal. >> > >> With an implicit "all-ranked" approval, the overall system would >> likely >> > >> violate later-no-harm with much higher frequency; by expressing a >> > >> preference between two dispreferred candidates one might >> unintentionally >> > >> put the higher of the two in contention. >> > >> >> > > >> > > dlw: I'd say empirically we'd see just how high of a frequency LNH >> would >> > be >> > > violated. Jameson Quinn had a hard time coming up with a pathological >> > > example for IRV3/AV3 and I imagine it'd be similar for the above. The >> > 1st >> > > stage would reduce the number of candidates to N+2 and it seems likely >> > that >> > > the N+2nd and N+3rd candidates in terms of "all-ranked" approval are >> less >> > > likely to be among the N winners. >> > >> > Hmm, ok. I'm operating on the assumption that voters will vote >> > strategically if doing so is easy, and will vote approximately >> > honestly if strategic voting is difficult. >> > >> >> okay. >> >> > >> > We're taking the top S+k winners and running some ideal STV method on >> > them; let's try to find an "easy" strategy. Here's my idea: >> > 1) Gather a set of related parties to form a majority-coalition. >> > 2) Have the coalition propose exactly S+k candidates. >> > >> >> good luck coordinating that.. >> >> 3) Ask coalition voters to vote for all of the coalition candidates in >> > any order they choose. >> > >> > Since a majority of candidates approve of every coalition candidate >> > and disapprove of every competing candidate, the coalition candidates >> > win the approval vote. >> > By adding the "approval" phase to the STV election, I'm able to turn a >> > simple majority into a 100% supermajority. >> >> >> > Is there a flaw in my strategy? (I don't think there is, but I may be >> > missing something.) If not, we'll either need to abandon a fixed >> > limit on the number of candidates or we'll need something more >> > sophisticated than a simple approval-vote to filter them. >> > >> >> dlw: It's not realistic. >> >> You'd need to have serious intra-party discipline to keep the no. of >> candidates down to S+2 >> and to get a majority of voters all to vote for all of that S+2 >> candidates. >> That is a serious coordination problem. >> >> But if it did happen then it'd "work" in terms of making the leading >> coalition of parties cast a broad net that strongly met the needs of most >> people. This would be much better than a bunch of non-competitive >> single-winner elections. In that case, we're in DINO land. >> > > By "strongly met the needs of most people" you appear to mean "met the > needs of a bare majority of people marginally better than the > alternatives". My concern is that in this scenario 25% of the electorate > would benefit substantially, 25% would benefit marginally, and the > remaining 50% would be arbitrarily worse off. That's essentially the same > worst-case behavior as the current majority-of-majorities setup, but with a > simpler strategy required to implement it. > > That being the case, I think we'd be better off with small-district STV > than with large-district STV with this sort of approval-based filtering. > > > > >> It may well be that these issues are all less severe than in the >> > >> deterministic alternatives to STV, but I still think they're enough >> to >> > >> merit consideration of nondeterministic alternatives. >> > >> >> > > >> > > In terms of the US's political culture, nondeterministic alternatives >> are >> > > not going to happen anytime in the near future and we need electoral >> > reform >> > > ASAP!!!! >> > >> > Sadly, I think both nondeterminism and STV share the "not going to >> > happen in the near future given political culture in the US" >> > classification, given that US law requires single-winner FPTP >> >> > elections for federal representation and the major parties (who >> > control the legislature and benefit greatly from FPTP) have no >> > incentive to change that law. >> >> dlw: STV need not end 2-party domination. Reforms that do not end 2-party >> domination are more fit in the US and should be the only ones pushed. >> And, as I've shown, it's implementation can be simplified. >> Thus, it can become a political jujitsu issue, whereby it is more >> rational >> for those in power to accommodate than to resist the proposed change. >> > > The belief that the 2-party system can accurately reflect voter consensus > relies heavily on the assumption that voters' differences of opinions > correlate sufficiently well with a single dimension of variability, so that > tending toward the center along a single axis produces centrist results on > all issues. I do not accept that assumption: in my experience, Americans > disagree along at least two axes that do not correlate perfectly (fiscal > policy and social policy). > > > > So as far as I can tell the only option for meaningful reform is a >> > constitutional amendment, and that means reforming 75% of the states >> > as a first step. This is not a short-term process. > > >> I think one could argue that the current law requiring single-winner >> elections is discriminatory twds minorities, and adopted under bad >> circumstances, and thereby unconstitutional. This would not require a >> constitutional amendment. >> > > I think you're perhaps overly optimistic about the willingness of courts > to overturn election law. But we'll see - I'd be thrilled to be proven > wrong about this one. > > ---- > Election-Methods mailing list - see http://electorama.com/em for list info > >
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