[EM] Rethinking Burial Detection Runoff

[C.Benham]

On 15/06/2023 7:17 pm, Kristofer Munsterhjelm wrote:

> James Green-Armytage has another suggestion for deterring burial: 
> https://www.jamesgreenarmytage.com/dodgson.pdf
>
> I haven't read it in detail, so perhaps the devil's in the details 
> about "plausible assumptions about how candidate decide". But what do 
> you think of that method?

In an earlier article James-Green Armytage discussed different 
Condorcet-IRV  methods, naming them all after people. I think there was 
Tideman, Woodall and "Benham".

Tideman (and "Smith-AV") fails Mono-add-plump and Mono-append. And both 
Tideman and Woodall are more complicated than Benham.

https://www.votingmatters.org.uk/ISSUE29/I29P1.pdf

The "one round version" of what he is now calling "Limited-Round 
Dodgson-Hare" is the same as Benham except that it specifies a 
"voluntary candidate withdrawal" option
and says nothing about whether equal-ranking should be allowed or how it 
should be handled.

I don't like candidate withdrawal options because I think the result 
should be determined as much as possible by voters via their ballots 
versus the machinations of candidates.

And for a practical proposal I don't like allowing above-bottom 
equal-ranking because it makes the method more complicated and/or more 
vulnerable to Pushover strategy.

But if it insisted on, then equal rankings (say A=B) should be 
provisionally interpreted as giving an equal fraction of a vote summing 
to 1, in this case half a vote each to A and B.

Then for the purpose of deciding which if any gets eliminated the A=B 
ballots should all be interpreted as giving a whole vote to whichever of 
the two had the higher tally on the
fractional basis and nothing to the one that had the lower tally.

 From the article you linked you linked to:

> Further, Green-Armytage et al. (2016) and Durand et al. (2016)
> both prove that for most single-winner voting rules including Hare, 
> adding a provision to elect
> the Condorcet winner when one exists can never make the rule 
> vulnerable to strategy in cases
> where it was not vulnerable already.

I'm a bit sceptical about that. I would have thought that it would make 
Hare (aka the Alternative Vote aka IRV) less vulnerable to Compromise 
but a bit more vulnerable to Burial.

In terms of criterion compliances the price we pay for gaining Condorcet 
is that we lose Later-no-Help, Later-no-Harm and Mono-add-Top.

Chris Benham





On 15/06/2023 7:17 pm, Kristofer Munsterhjelm wrote:
> On 6/15/23 07:47, Forest Simmons wrote:
>> Chris,
>>
>> I like your new Condorcet method, and consider it to be a much more 
>> practical suggestion than any of my sincere CW finder ideas currently 
>> in progress.
>>
>> The ballot profile you provided to illustrate your LV Sorted Margins 
>> burial resistant method, ended up electing A, which we considered to 
>> be better than electing B, because we thought that with some positive 
>> probability the ballot profile might be a result of the B faction's 
>> insincere order reversal .... changing sincere 44 B>A to 44 B>C, i.e. 
>> the B faction burying A under C ... so that electing B, like just 
>> about every other method under the sun, would encourage bad behavior.
>>
>> Is it insulting to voters to build in safe guards that make insincere 
>> truncations or burials less likely to pay?
>>
>> Is it insulting to lock your front door when leaving town for a few 
>> dsys?
>
>> Going outside the strict Universal Domain by allowing truncations, 
>> equal rankings, approval cutoffs, or other levers, offer additional 
>> expressiveness that can reduce incentives for burial, compromise, etc.
>
> James Green-Armytage has another suggestion for deterring burial: 
> https://www.jamesgreenarmytage.com/dodgson.pdf
>
> I haven't read it in detail, so perhaps the devil's in the details 
> about "plausible assumptions about how candidate decide". But what do 
> you think of that method?
>
>>
>> I've been experimenting with how far we can get with two sets of 
>> ballots ... one possibly strategic set, for the purpose of determing 
>> the finalists and runoff order ... and the other set dedicated solely 
>> to the kind of runoff that elects the sincere CW whenever there is one.
>
> This is still an interesting venue, of course. I've updated the 
> Electowiki page about Condorcet loser to include information that a 
> manual runoff method always passes honest Condorcet loser (assuming no 
> drop in turnout).
>
> At some point I would like to do a minimum strategy evaluation of 
> methods with two rounds, but I've currently been occupied with 
> cleaning up some other code in my election simulator quadelect so that 
> I can automatically check for clone failures, monotonicity, etc. the 
> same way I can check for strategy failures; and so that I can classify 
> strategy failures as burial, compromise, or other.
>
> Maybe, eventually!
>
> -km