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

[Colin Champion]

Kristofer - firstly an apology, I gave the result for Condorcet//fptp 
rather than Condorcet,fptp. The correct results are: minimax 64%, 
condorcet+fptp 59%, copeland,fptp 53% (vice 47%).
    As for other good, simple methods, I find it hard to say. Lots of 
reasonably accurate methods are aesthetically objectionable for a range 
of reasons; for instance I think that Condorcet+random is at least as 
good as Condorcet+fptp (presumably because it's hard to manipulate), but 
no one would be happy to see so prominent a role given to chance.
    'Minisum' - which I think is the same as Tideman's "Simplified 
Dodgson Rule" - is almost as good as minimax, but I can't see why anyone 
would choose it in preference (it looks rather similar). It has the 
drawback of having received little discussion in the literature.
    Copeland,dblv is somewhat better than Copeland,fptp. The double vote 
elects the candidate with the greatest sum of first and second 
preferences. It's a lousy voting method but an effective tie-break 
because it tends to blow up in the face of anyone who attempts tactical 
voting.
    Copeland,minimax is very good, but again why bother? Its resistance 
to tactical voting comes from minimax; Copeland's method is little more 
than a sleeping partner.
    Copeland//Borda (which is one interpretation of Dasgupta/Maskin) is 
probably slightly better than Copeland,fptp.
    Benham's method and Black's are both pretty good. So are some of the 
more complicated methods such as RP.

All this subject to the usual caveats about software reliablilty. The 
results table is at 
https://www.masterlyinactivity.com/condorcet/condorcet.html#results
    Colin

On 18/02/2023 11:47, Kristofer Munsterhjelm wrote:
> On 2/18/23 10:42, Colin Champion wrote:
>
>>     But then I don't favour Kristofer's proposal either. My 
>> evaluation suggests that burial is a particular threat for Condorcet 
>> methods, and that in its presence their accuracies are: minimax 64%, 
>> condorcet+fptp 59%, copeland,fptp 48%. [Usual disclaimers apply.]
>
> That's fair; I was simply trying to find a minimal change to the 
> method that would at least grant Smith or something like it.
>
> Really, what I'm concerned about is that there's such a, for lack of a 
> better term, steep cliff from the Condorcet domain down to the 
> Plurality domain. So everything's nice as long as you play on top of 
> the mountain, but if you misstep (i.e. produce a cycle), then you 
> don't gradually degrade, you fall directly into plain old Plurality, 
> with all of its vote splitting problems. The discontinuity seems like 
> something that's just asking to be exploited.
>
> Do you know of any alternate "bang for the buck" methods that would be 
> simple enough to be accepted?
>
> -km

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