[EM] STV+AV

[David L Wetzell]

On Sat, Feb 4, 2012 at 2:07 PM, Bryan Mills <bmills at alumni.cmu.edu> wrote:

> > From: Bryan Mills <bmills at alumni.cmu.edu>
>> > To: David L Wetzell <wetzelld at 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.)
>

dlw; Well, proportionality matters to the extent it makes the control of
the legislative body in question more likely to be competitive...  and even
the best laid plans of mice and men go awry.

>
> Suppose we have two parties with a 50/50 split
>
How about a 45-45 with 10% being random... this wd keep the 20% non-safe
seats more likely to be competitive, even w. attempts at gerrymandering.


> 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
>

> 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.
>

dlw:But don't you see, this does constrain the damage possible via
> gerrymandering.  You've given the extreme case.  If it had been all
> single-winner districts, the max someone could theoretically get for their
> party would be just shy of 100%.  So the variance of the bias introduced by
> gerrymandering is dwarfed to be a small fraction of what it could have been.
>

And, it'd be easier for a minor party to gain ground and either threaten to
spoil things for the party who'd get 3 seats or to take that seat away.
 This means some power and even more influence is redistributed because of
the use of American forms of PR.

Or if there's a significant fraction who are independents (completely or
leaning left or right) then it'd be harder for a party to rig the election
in this setting.  In an STV election, they'd have to limit their candidates
to 2 or 3 and that isn't easy to do without giving more groups within the
party more exit threat that thereby increases their voice within the party.


So the party itself will be changed by virtue of the changes in the rules.
 Even if we still get 2 major parties and the districts get gerrymandered
some, there will be two different major parties and lower barriers of entry
for minorities/third parties to get voice on issues they care about.

>
> > 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.
>>
>
But you are giving the party's too much credit and neglecting the problems
of balancing intra-party democracy and intra-party discipline.  Plus,
there's the greater "bias" due to the greater ease w. which a 3rd party
could make inroads into the situation.  That entry threat is even more
credible in some gerrymandered situations...

>
>> 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.
>

dlw: We don't need to fix the biases in total, nor do we need to get them
out of power to reduce their ability to game the system and to change the
play of the game needed for them to stay in power in ways that will make a
difference!

>
> 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.
>

Aye, but they'd at least be in a better position to be swing voters who get
more say-so as a result.  As JQ makes clear, gerrymandering is not an exact
science and there's less margin to error with a 5-seat PR-Droop quota in
use, which can thereby be gamed by outsiders who can shake up the system in
important wways..

>
>
> > >> 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.
>

dlw: Only the supporters of a major party that refuses to moderate itself.
 Those who more often need protection for their rights, since they are more
likely to be w.o. representation will be able to vote sincerely.   This
prevents a major party from getting captured by its tails, as unfortunately
happens too easily in the US.

>
>
> > >> 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".
>

No, I mean that more of the people in the party coalition have a more
credible exit threat and thereby more voice within the setting of its
priorities.

It's not easy to hold together a broad coalition in real life.


> 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.
>

dlw: If the bigger districts make it more likely that the percent diff
between the "ruling coalition" and those outside it is smaller then there's
a higher chance that things could switch or that the bigger parties within
the ruling coalition will need to partner with parties outside it in the
future, which will affect how they treat them...

So long as the slices of the population who are in the 25-25-50 category
may shift, this worse case scenario ain't so bad.

>
> 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.
>

I agree.  And the truth is you don't see too many large-district STVs in
practice, as it is.
The proliferation of candidates brings its own difficulties.

 > >> 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).
>

dlw: Aye, but if we get more voices getting heard, the principal components
of these axes can be changed so that there is a center and the assumption
is more likely to be true.


> > 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.
>

Well, Clarence Thomas likes cumulative voting, not unlike what was used in
IL for their state reps elections from 1870-1980, as an anti-discriminatory
measure and it cd be argued that the sort of votes is less important than
the quota used.   Also, Barack Obama introduced legislation to bring back
cumulative voting in 2001 while he was a state senator.  We need to make
sure that he appoints SCJs who will do the right thing.

dlw
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