[EM] Hey guys, look at this...

[Colin Champion]

I asked Kristofer whether Condorcet+FPTP complied with the Condorcet 
Loser criterion. He replied "probably not" with a sketch proof, and then 
gave the following example.

<quote>
[preliminary election]

40: L>C>R
42: R>C>L
10: C>L>R

R is the Condorcet loser and Plurality winner. (L is the IRV winner.)

Now clone C, the CW:

40: L>Ca>Cb>Cc>R
42: R>Cb>Cc>Ca>L
10: Cc>Ca>Cb>L>R

There's no CW, so Plurality elects R, the Condorcet loser. 
(Incidentally, R ties for first in minmax.)

Seems OK. Verified with 
https://web.archive.org/web/20220403135047/http://www.cs.angelo.edu/~rlegrand/rbvote/calc.html. 

</quote>

I'd wondered whether Robert didn't have any intellectual commitent to 
the criterion, but had used it in argument against IRV and therefore 
found his options limited.

CJC

On 19/02/2023 17:31, Kristofer Munsterhjelm wrote:
> On 2/19/23 16:36, Colin Champion wrote:
>> "Politicians and the voting public would not accept anything more 
>> complicated than X" is my own favourite line of argument - but I 
>> substitute my own value for X(minimax). I know that my judgement is 
>> coloured by my preferences. There's a surprising degree of dissent 
>> over which methods are simpler than which, and where the boundary 
>> should be drawn. People who deal directly with politicians and the 
>> voting public can no doubt get closer to the truth than people whose 
>> interest is predominantly theoretical, but I wish there was an 
>> authoritative and objective source of information. If only some 
>> behavioural psychologist was funded to investigate the question...
>>
>> To be finicky, the issue isn't exactly one of simplicity but rather 
>> one of psychological acceptability, which includes the notions of 
>> whether a method "makes sense" to the average onlooker, and whether 
>> it is seen as conferring legitimacy on its winner rather than being 
>> an unmotivated piece of jiggery pokery.
>>
>> Notwithstanding all this... you and Robert may well be right.
>
> FWIW, I suspect the complexity people are willing to accept depends on 
> their trust in the political process in general. For instance, some 
> local New Zealand elections use Meek's method, which is complex 
> however you put it.[1] And I wouldn't be prepared to explain the 
> pretty messy greedy algorithm used to allocate party list top-up seats 
> here (in Norway), but people seem to accept it.[2]
>
> I don't think Robert could use minmax because the criterion he's using 
> is "if more people prefer X to Y than vice versa, then Y is not 
> elected". That seems to imply at least Condorcet loser. I'm not sure, 
> though -- if you're particularly critical, you could even say it 
> implies Smith, but I don't think Robert had that in mind.
>
> -km
>
> [1] I wonder what the legal language for *that* is... it's basically 
> impossible to do by hand.
> [2] IMHO, biproportional apportionment is *much* simpler. I suspect 
> what's keeping it from being changed is mostl inertia.

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