[EM] Manipulability stats for (some) poll methods

[Closed Limelike Curves]

>
> Seats/districts where that would even be a theoretical possibility would
>> be rare. I did read a report in a newspaper some time in the 1980s that the
>> conservative Liberal Party toyed with the idea of doing that in one seat,
>> but rejected the idea on the grounds that it would undermine the perceived
>> integrity of the election process and so the legitimacy of the winner.
>
> Damn. That certainly wouldn't happen in the current political climate here
in the US.

That said, our Democratic party encourages this kind of strategy often.
Usually, that's not by instructing their supporters to raid the opposing
primary; instead they create "attack advertisements" that are intentionally
awful. ("This far-right candidate wants to increase the debt by SLASHING
INCOME TAXES FOR THE MIDDLE CLASS!")

On Sun, Apr 28, 2024 at 8:01 PM Chris Benham <cbenhamau at yahoo.com.au> wrote:

> CLC,
>
> Chris—here in the United States, pushover is well-known and frequently
> used, in the context of partisan primaries. We refer to it as "raiding".
>
>
> That doesn't surprise me in the least. Your crazy party primary system is
> a big open red-carpet invitation to pushover strategists.  I think Nikki
> Hayley was Trump's last opponent in the Republican primaries to drop out.
> On YouTube I saw one of her "supporters" interviewed.
> He openly stated that he was only participating in that contest to try to
> "stop Trump", and no matter who was the Republican nominee he was
> definitely intending to vote Democrat in the general election.
>
> In October last year Rob Lamphier asked me about Push-over in Australia:
>
> >* Is "pushover" strategy common in Australian elections, and commonly **named by that name?
> *
> No and no.  I've only ever come across the term here, and from that Blake Cretney page.
>
> Seats/districts where that would even be a theoretical possibility would be rare. I did read a report in a newspaper some time in the 1980s that the conservative Liberal Party toyed with the idea of doing that in one seat, but rejected
> the idea on the grounds that it would undermine the perceived integrity of the election process and so the legitimacy of the winner. Bear in mind that we have "compulsory voting" which is popular, because it is widely accepted that voting is a civic duty.
>
> In that district the highly predictable FPP order was Right > Centre-Right > Centre-Left, or if you want the parties' names Liberal > Australian Democrats > Labor.
>
> It was also highly predictable that nearly all of the Labor voters would give their second preference to the Democrat and that a big majority of the Democrat voters would give their second preference vote to the Liberal.  (Bear in mind that truncation isn't allowed).
>
> In that circumstance the Liberals could have organised for some of their supporters to vote Labor to "rescue" that candidate from being eliminated, so that instead the Democrat will be eliminated and then the Liberal will win in the pairwise contest with Labor.   BTW, the Democrat was the sitting member (and it may have been that party's only seat in the state parliament,Labor and Liberal are the two major parties).  Of course the Democrat was the Condorcet winner, but no-one  even had that concept.
>
>
> I suspect Australia doesn't have any examples of turkey-raising because it
> only has two major parties in its IRV seats, at which point the strategy is
> pointless.
>
>
> That is far from the main reason, and isn't universal. It's obviously much
> more difficult than in the US with a primaries system or a Top-Two Runoff.
> In that situation once the strategists have achieved their first objective,
> getting the "turkey" into the final (or the general election) they can then
> vote "honestly" to help defeat that candidate in the final decisive stage.
>
> But with Hare, the strategists have to stick with their insincere vote
> supporting the turkey in the final and just hope that enough other voters
> will overwhelm their votes and defeat the turkey.  This obviously makes the
> risk of backfire (i.e. the turkey winning) much greater.
> The strategists have to be careful that there aren't too many of them
> (while of course it won't work if there are too few).
>
> One mistake I think that voting reform enthusiasts in the US make is that
> they over-estimate the effect of the electoral system/method on the
> political culture as well as over-simplifying it.
>
> For example they want more viable political parties and seem to assume
> that all two-party dominated systems are roughly equivalent. But the one
> with Hare is much better. In the FPP landscape the major parties can foist
> unpopular candidates and/or policies onto the voters and say "You have to
> vote for us because otherwise you'll just be wasting your vote and letting
> your Greater Evil other major party win."  But in the Hare landscape
> (especially with relatively easy ballot access) their ability to do that is
> sharply curtailed.
>
> Because the voters can then just turn around and nominate and support
> independent candidates that support the same "side of politics" as their
> usual favourite major party, with a chance to defeat the major party
> candidates without helping the "wrong" one to win.
>
> So one possible effect of replacing FPP with Hare is just that the two
> major parties will both improve their behaviour and sensitivity to voters
> to stop that from happening, and the whole system will serve voters much
> better but still remain "two-party dominated".
>
> The political culture of Australia assures that any attempts at Pushover
> strategy would be kept very quiet, so I suppose I can't guarantee that it's
> never been tried or succeeded. But I'd be be surprised.
>
>
> Chris B.
>
>
> On 29/04/2024 10:05 am, Closed Limelike Curves wrote:
>
> Chris—here in the United States, pushover is well-known and frequently
> used, in the context of partisan primaries. We refer to it as "raiding".
> Usually it's difficult to notice, and I suspect the same is true in
> Australia. The only difference is here in the United States we manage to
> notice it from time to time, because what happens is candidates will run
> big advertisement operations that aim to promote an extreme candidate in a
> primary and give an easy win. I can't prove the same thing happens with
> voters, but I'm not sure how you *would *prove that.
>
> I suspect Australia doesn't have any examples of turkey-raising because it
> only has two major parties in its IRV seats, at which point the strategy is
> pointless.
>
> On Sun, Apr 28, 2024 at 4:14 PM Chris Benham <cbenhamau at yahoo.com.au>
> wrote:
>
>> Michael—you're right that it means favorite-burial (cutting the "head"
>> off a ballot). The term is quite old, though (older than "favorite
>> betrayal" or "favorite burial" I believe)
>> <https://www.cambridge.org/core/product/identifier/S0003055400194481/type/journal_article>
>> .
>>
>>
>> I don't like either term.  For me, "burial" refers to something a voter
>> does to a candidate in the hope that will cause that candidate to lose to a
>> candidate the voter prefers, and not just to any insincere down-ranking.
>> So "favorite-burial" is  an oxymoron that Mike O. likes to use.
>>
>> "Favorite Betrayal" meaning to insincerely down-rank one's favourite, is
>> ok, but that could either be Compromise strategy (insincerely up-ranking X
>> to decrease the chance that X will lose to a candidate you like less) or
>> Push-over (insincerely up-ranking X to increase the chance that X will lose
>> to say F that you like better, instead of F losing to some Y that you like
>> less).
>>
>> An attempt was made to standardise the terminology here quite a while ago:
>>
>> http://condorcet.org/emr/defn.shtml
>>
>> *burying*
>> Insincerely ranking an alternative lower in the hope of defeating it.
>>
>> *compromising*
>> Insincerely ranking an alternative higher in the hope of getting it
>> elected.
>>
>> *push-over*
>> The strategy of ranking a weak alternative higher than one's preferred
>> alternative, which may be useful in a method that violates monotonicity
>> <https://web.archive.org/web/20090613041320/http://condorcet.org/emr/defn.shtml#monotonicity>
>>
>> *monotonicity*
>> The property of a method where an alternative can never be made to
>> succeed by being ranked lower on some ballots.  Doing this is using the "
>> push-over
>> <https://web.archive.org/web/20090613041320/http://condorcet.org/emr/defn.shtml#push-over>"
>> strategy.
>>
>>
>>
>> The genius of  STAR Voting is that it apparently technically doesn't
>> "violate monotonicity", but it is vastly more vulnerable to Push-over than
>> IRV which does, as I've explained previously.
>>
>> I find the question of whether there have been mistakes or exaggerations
>> or false claims made by the IRV promoters to be completely irrelevant to,
>> and a separate question from, whether its adoption in the US should be
>> supported.
>>
>> Of more concern to me are the details of the ballot rules and
>> restrictions. I think it is more democratic for it to be relatively easy to
>> get on the ballot so as to allow the voters a wider choice of candidates. I
>> understand that typically voters are limited to 7 different "ranking
>> levels".  Well say there are 9 candidates and my two least-preferred
>> candidates are the two front-runners and I have a preference between them.
>> If I vote sincerely my vote is just as wasted as if I had voted sincerely
>> in FPP.
>>
>> IRV then doesn't have Clone Independence.  One of the main points of
>> ranked-ballot versus FPP is to reduce the involuntarily wasted vote as much
>> as possible.
>>
>> If such restrictive ballot rules are unavoidable, then I lose my
>> enthusiasm for IRV or Benham in favour of something with a truncation
>> incentive (and that is happy with equal-ranking if that isn't a problem for
>> the ballot rules) such as Smith//Approval (implicit).
>>
>> Properly implemented Hare's  Compromise incentive is practically nothing
>> by comparison with that of FPP, and no-one in Australia notices it.  I
>> estimate it is also quite a bit weaker than that of STAR.  Pushover
>> strategy in Hare is relatively difficult and risky in Hare and as far as I
>> know it's never been tried in Australia.  Whereas STAR is a "festival of
>> Push-over" farce/nightmare.
>>
>> And while (like STAR) it fails Condorcet, it has a solid set of
>> "representativeness" criterion compliances that together can be thought of
>> as weakened Condorcet and are worth quite a lot.
>>
>> They are Dominant Coalition (a better stronger version of Mutual Majority
>> that so of course implies it) and Dominant Mutual Third and Condorcet
>> Loser.   STAR only meets the last of those, the weakest.
>>
>> Chris B.
>>
>>
>> On 29/04/2024 5:08 am, Closed Limelike Curves wrote:
>>
>> Michael—you're right that it means favorite-burial (cutting the "head"
>> off a ballot). The term is quite old, though (older than "favorite
>> betrayal" or "favorite burial" I believe)
>> <https://www.cambridge.org/core/product/identifier/S0003055400194481/type/journal_article>
>> .
>>
>> On Sun, Apr 28, 2024 at 12:02 PM Michael Ossipoff <email9648742 at gmail.com>
>> wrote:
>>
>>> Of course I’m just guessing, but my guess is that “decapitation” is
>>> Closed’s new name for favorite-burial.
>>>
>>> Closed sometimes in invents new names without define them.
>>>
>>> IRV indeed shares Plurality’s need for favorite-burial
>>> defensive-strategy. I don’t like that, & wouldn’t propose IRV. There are a
>>> number of places where IRV is (the only electoral reform) up for enactment
>>> this year, In spite of that very  unlikeable strategy-need, I wanted to
>>> help campaign for its enactment, in the hope that the voters who’ve enacted
>>> it didn’t do so because they intend to bury their favorite, & so so won’t
>>> do so.
>>>
>>> But, because IRV is being fraudulently sold to them, with intentional
>>> lies, we can’t count on how people will vote when they find out about what
>>> they’ve enacted…when they find out about the lie.
>>>
>>> Therefore, regrettably, we shouldn’t support “RCV”.
>>>
>>>
>>> On Sun, Apr 28, 2024 at 11:15 Chris Benham <cbenhamau at yahoo.com.au>
>>> wrote:
>>>
>>>> Limelike,
>>>>
>>>> Can you please define and explain the "decapitation" strategy?   I
>>>> haven't heard of it.
>>>>
>>>> And can you elaborate a bit on this? :
>>>>
>>>> IRV is a good example of this. It's *usually* not susceptible to
>>>> strategy (in the IAC model), but I think of it as one of the most
>>>> strategy-afflicted methods on this list. It's vulnerable to some
>>>> particularly-egregious strategies (decapitation), ones that are complex or
>>>> difficult to explain (pushover), and many strategies [that?] don't have a
>>>> simple defensive counterstrategy available (like truncation).
>>>>
>>>>
>>>> Chris B.
>>>>
>>>> On 29/04/2024 2:31 am, Closed Limelike Curves wrote:
>>>>
>>>> Hi Kris, thanks for the results! They're definitely interesting.
>>>>
>>>> That said, I'm not sure how useful a metric raw probabilities provide;
>>>> I don't think they provide a very strong measure of how *severely* each
>>>> system is affected by strategy. Missing are:
>>>> 1. How much do voters have to distort their ballots? Is it just
>>>> truncation, compression (as with tied-at-the-top), or full decapitation?
>>>> 2. How hard is it to think of the strategy? Counterintuitive strategies
>>>> (e.g. randomized strategies or pushover) require large, organized parties
>>>> to educate their supporters about how to pull it off. This could be good or
>>>> bad depending on if you like institutionalized parties. Good: sometimes
>>>> people can't pull it off. Bad: this creates an incentive for strong parties
>>>> and partisanship. See the Alaska 2022 Senate race, where Democrats pulled
>>>> off a favorite-betrayal in support of Murkowski to avoid a center-squeeze.
>>>> 3. Is a counterstrategy available?
>>>> 4. How feasible is the strategy (does it involve many or few voters)?
>>>> 5. How bad would the effects of the strategy be? Borda is bad not just
>>>> because it's often susceptible to strategy, but because it gives turkeys a
>>>> solid chance of winning.
>>>>
>>>> IRV is a good example of this. It's *usually* not susceptible to
>>>> strategy (in the IAC model), but I think of it as one of the most
>>>> strategy-afflicted methods on this list. It's vulnerable to some
>>>> particularly-egregious strategies (decapitation), ones that are complex or
>>>> difficult to explain (pushover), and many strategies don't have a simple
>>>> defensive counterstrategy available (like truncation).
>>>>
>>>> A low-probability but occasionally high-impact strategy might be the
>>>> worst of both worlds; voters get lulled into a false sense of security by a
>>>> few elections where strategy doesn't matter, then suddenly find a candidate
>>>> they dislike elected because they failed to execute the appropriate
>>>> defensive strategy.
>>>>
>>>> ----
>>>> Election-Methods mailing list - see https://electorama.com/em for list info
>>>>
>>>>
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