[EM] Portland specifics, and ovals for approval cutoff
Richard, the VoteFair guy
electionmethods at votefair.org
Sun Jul 14 10:21:50 PDT 2024
On 7/13/2024 5:39 PM, Closed Limelike Curves wrote:
> ... my guess is the effect of STV is probably going to be limited
> compared to other methods, because STV is only proportional for solid
> coalitions, i.e. voting blocs moving in perfect lockstep with each
> other, and only if they exceed a full quota. ...
When using STV, coalitions don't need to be "solid."
STV calculations automatically identify de-facto "coalitions." Each
candidate can be thought of as a de-facto coalition.
One way to think of this concept is that STV gives any coalition a
"second try" when filling the second seat, and a "third try" when
filling the third seat.
In contrast, IRV provides only "one try" for a coalition to elect their
candidate. So for IRV, a "solid" coalition voting with the same tactic
does have an advantage compared to a loose (non-solid) coalition.
I'm not saying STV is better than PAV. I'm saying this specific
criticism of STV -- thinking that a coalition must be "solid" -- is not
a valid reason to dismiss STV.
Richard Fobes
On 7/13/2024 5:39 PM, Closed Limelike Curves wrote:
> Ahh, yeah, any PR method will outperform winner-take-all on this metric.
> If cities are using STV for their city councils, that might imply
> single-winner IRV actively reduces minority representation.
>
> That said, my guess is the effect of STV is probably going to be limited
> compared to other methods, because STV is only proportional for solid
> coalitions, i.e. voting blocs moving in perfect lockstep with each
> other, and only if they exceed a full quota. So, for example, if ethnic
> minorities tend to vote for a mix of white and minority candidates, or
> if they're split across party lines (e.g. Hispanics only go about 60-40
> for Democrats), this will tend to break up and dilute their interests.
> It's not enough to have a quota of Hispanics who rate Hispanic
> Republicans and Hispanic Democrats highly; you need to have a full quota
> rank /either/ a Hispanic Republican or a Hispanic Democrat at the top of
> their ballots. The effect is the same as center-squeeze, where your vote
> gets "stuck" with a weak candidate who nevertheless has enough first
> preferences to stay in the race for several rounds. By the time this
> candidate is eliminated, the more-electable candidates with fewer first
> preferences have been defeated.
>
> But from what I can tell, this is much trickier to resolve than
> center-squeeze; proportional Condorcet methods don't seem to have any
> guarantees on how out-of-whack a coalition can get, although I think
> Schulze STV has a nice local stability property.
>
> Most ethnic minorities aren’t solid coalitions, although
> African-Americans happen to be so overwhelmingly Democratic they might
> act like one. Something like PAV that approximately satisfies the core
> property should do better at giving minority voters more representation.
>
> On Thu, Jul 11, 2024 at 8:40 PM Richard, the VoteFair guy
> <electionmethods at votefair.org <mailto:electionmethods at votefair.org>> wrote:
>
> On 7/11/2024 10:47 AM, Closed Limelike Curves wrote:
> > ... given there's no theoretical basis to think IRV would affect
> > city council and mayoral seats differently. ...
>
> In the new Portland elections, "ranked choice voting" for city-council
> seats is STV (the Single Transferable Vote) with three seats per
> district, whereas "ranked choice voting" for Portland mayor is
> single-winner IRV (instant-runoff voting).
>
> Of course Portland's three-seats-per-district STV city-council
> elections
> are going to yield more gender and racial diversity compared to
> single-winner IRV for electing Portland's mayor.
>
> Richard Fobes
>
>
> On 7/11/2024 10:47 AM, Closed Limelike Curves wrote:
> > I'm going to go ahead and say I'm skeptical either of these
> results will
> > replicate, given there's no theoretical basis to think IRV
> would affect
> > city council and mayoral seats differently. My guess is both results
> > would disappear if you used a hierarchical/partial pooling model to
> > reduce the noise in the estimates.
> >
> > On Thu, Jul 11, 2024 at 10:45 AM Michael Garman
> > <michael.garman at rankthevote.us
> <mailto:michael.garman at rankthevote.us>
> <mailto:michael.garman at rankthevote.us
> <mailto:michael.garman at rankthevote.us>>>
> > wrote:
> >
> > And that’s bad! But it doesn’t negate the point I made. In
> council
> > races it helps. And that’s good!
> > On Thu, Jul 11, 2024 at 1:44 PM Closed Limelike Curves
> > <closed.limelike.curves at gmail.com
> <mailto:closed.limelike.curves at gmail.com>
> > <mailto:closed.limelike.curves at gmail.com
> <mailto:closed.limelike.curves at gmail.com>>> wrote:
> >
> > > In mayoral elections, RCV seems to *decrease* gender and
> > racial/ethnic diversity.
> > Sounds substantial!
> >
> > On Thu, Jul 11, 2024 at 10:28 AM Michael Garman
> > <michael.garman at rankthevote.us
> <mailto:michael.garman at rankthevote.us>
> > <mailto:michael.garman at rankthevote.us
> <mailto:michael.garman at rankthevote.us>>> wrote:
> >
> > > In city council elections, RCV has a small but
> positive
> > effect on racial/ethnic diversity
> > Sounds substantial!
> >
> > On Thu, Jul 11, 2024 at 1:26 PM Closed Limelike Curves
> > <closed.limelike.curves at gmail.com
> <mailto:closed.limelike.curves at gmail.com>
> > <mailto:closed.limelike.curves at gmail.com
> <mailto:closed.limelike.curves at gmail.com>>> wrote:
> >
> > Empirically, IRV adoption has no substantial
> effects on
> > diversity
> >
> <https://www.newamerica.org/political-reform/reports/rcv-impact-on-candidate-entry-and-representation/ <https://www.newamerica.org/political-reform/reports/rcv-impact-on-candidate-entry-and-representation/>>. In theory, I'd expect a small decrease in representation for minorities, because people of color tend to have higher rates of spoiled ballots, so IRV should hit them the hardest.
> >
> > In general, the theoretical advantages of IRV
> over FPP
> > are outweighed by its practical costs (spoiled
> ballots,
> > lower trust in elections, cost, etc.).
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