[EM] Endorsement for STAR voting

[Michael Ossipoff]

I emphasize that I only propose RP(wv) to people & jurisdictions who insist
on ranking, or to political parties who have been offering “RCV” because
progressives want ranking.

Approval is my main proposal.

On Tue, Mar 19, 2024 at 19:54 Michael Ossipoff <email9648742 at gmail.com>
wrote:

>
>
> On Tue, Mar 19, 2024 at 14:07 Closed Limelike Curves <
> closed.limelike.curves at gmail.com> wrote:
>
>>  *every sufficiently well-designed voting system converges to score*.
>>
>
> ???
>
> :-D
> ———
> Someone in this conversation said that he simplifies the definition of RP
> for simplicity. What???
>
> There’s no need to dumb-down or make vague the RP definition. When
> proposing RP, I state its actual definition, which is simple, & powerfully,
> obviously & intuitively motivated.
>
>
>
> We have an impossible trilemma:
>> 1. If your voting system doesn't respond to strategic exaggeration, it's
>> not responsive to voters. (If you rank a candidate 1st, they damn well
>> *should* do better than if you put them in the middle!)
>> 2. If it responds to exaggeration but penalizes compression (ranking
>> several candidates first makes them less likely to win, compared to ranking
>> them all), it's Duvergerian (favorite-betrayal incentive).
>> 3. If it responds to exaggeration but doesn't penalize compression, it's
>> approval voting (at least if you have strategic voters).
>>
>> Of these, it seems like voting theorists have converged on #3 being the
>> least-bad option, although some systems try to compromise.
>>
>> STAR tries to compromise between 2 and 3, but mostly sticks close to 3.
>> It has a favorite-betrayal incentive, but it's negligible. (Only possible
>> if the score-runner-up without your vote would win the runoff, but the
>> score-runner-up with your vote would lose). It also gives slight
>> decompression at the top end (sometimes you'll want to rate 4 stars instead
>> of 5, to make sure your favorite beats your second-favorite).
>>
>> The only way I can see us moving past this trilemma is if we have some
>> outside-the-box mechanism. We can't *just* look at vanilla voting
>> systems that pick the best candidate from a pool. We need to look at
>> mechanisms that make support costly *across *races or decisions. Voters
>> need to be on the hook if they try to just top-rate all their favorites,
>> but that incentive has to come from paying a cost somewhere *other* than
>> inside the race. If you try to make it costly to support multiple
>> candidates at once (like cumulative voting does), you just get
>> favorite-betrayal and plurality again.
>>
>> Improvements on approval voting will probably come from some direction
>> like working out how to make the VCG mechanism more resistant to coalitions
>> and letting voters rate candidates across multiple races. Most decent
>> voting systems are already up against the brick wall of top-shelf methods
>> labeled Score/Approval/STAR/RP/Tideman alternative—notice that all of these
>> except STAR were proposed more than 30 years ago, all give similar results
>> in practice, and we *still* haven't figured out a way to beat them!
>>
>> On Tue, Mar 19, 2024 at 5:31 AM Kristofer Munsterhjelm <
>> km_elmet at t-online.de> wrote:
>>
>>> On 2024-03-19 02:05, Rob Lanphier wrote:
>>> > Hi folks
>>> >
>>> > I was asked to provide a quote supporting STAR voting by the
>>> Equal.Vote
>>> > Coalition (equal.vote <https://equal.vote>).
>>>
>>> [snip]
>>>
>>> > I think the Condorcet winner criterion (CWC) matters a lot more than
>>> > "cardinal" advocates often suggest, but it's almost impossible for me
>>> > to imagine a credible election scenario where the STAR winner and a
>>> > strictly CWC-compliant method would differ.   More to the point, with
>>> that final
>>> > pairwise comparison, STAR virtually guarantees that a majority of
>>> voters
>>> > prefer the winner to the runner up.  And it's 1000% better than
>>> RCV/IRV
>>> > as promoted by FairVote.
>>>
>>> The obvious thing that comes to mind that could make STAR fail Condorcet
>>> is the clone problem. It doesn't even have to be a deliberate strategy:
>>> it could just emerge from the incentives. Suppose that there are three
>>> parties: Left, Center, and Right. Say that Left often is the Range
>>> winner, but the Left-first voters is a minority so Center comes in
>>> second and wins the runoff.
>>>
>>> Then a second near-Left party has an incentive to grow, because if it
>>> can get strong enough, it knows that the left voters will also give it a
>>> high rating, so that the runoff now consists of two left-wing
>>> candidates, and thus one of them will win. If the rules permit a party
>>> to field multiple candidates, then it's even easier: the existing Left
>>> party can just field two.
>>>
>>> Over time, this incentive to entry could reduce STAR to Range.
>>>
>>> I agree that if we are to take strength of preference seriously (in the
>>> vNM sense, as I described in my other post), then it should, as you put
>>> it, take nuance into account, but not too much of it. I have some
>>> thoughts about how that could be done (I've written posts about it), but
>>> the methods would be considerably more complex.
>>>
>>> Or if you're on the ordinal side of the divide,
>>> Smith//Range(renormalized) would fix the clone problem for rated clones.
>>> But it wouldn't be monotone.
>>>
>>> The clone problem and entry incentive could be detected by simulation by
>>> replicating James Green-Armytage's work in the paper where he showed
>>> that IRV has an exit incentive. To my knowledge, nobody has done so yet,
>>> which would explain why you haven't seen any simulations of that form.
>>>
>>> -km
>>> ----
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>>> info
>>>
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>>
>
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