Briefly why I prefer Reg-Champ to Smith//Con

[Bruce Anderson]

On May 27,  5:00pm, Steve Eppley wrote:
> Subject: Re: Attachment CRITTBL1
> Bruce, you've provided a table of some ranked ballot voting methods
> which meet or fail to meet 7 criteria.  Quite a few of the methods
> meet all 7 criteria, including Smith//Condorcet.  
> 
> You've also written that you prefer Regular-Champion to
> Smith//Condorcet, but I don't recall you explaining why. 
> 
> Since we're probably going to poll ourselves soon on methods, I'd
> like to hear your reasoning; otherwise I feel compelled based on 
> the discussion so far to rank Smith//Condorcet higher than
> Regular-Champion. 
> 
> I presume that you're planning to post definitions of the methods 
> mentioned in the table.  I'm looking forward to that, because many of 
> the methods' names are unfamiliar to me and because I'm curious about 
> how Condorcet is defined (and by whom).
> 
> ---Steve     (Steve Eppley    seppley at alumni.caltech.edu)
> 
>-- End of excerpt from Steve Eppley

If you, or others, would like more details on any of the voting methods I 
recently described, please let me know which ones, and what kind of additional 
details you would like to see.  Otherwise, I will assume that the descriptions 
are adequate for your purposes.

I have not get posted why I prefer Regular-Champion to Smith//Condorcet.  
Briefly, the reasons are as follows.

First, from what I have seen so far, it seems to me that the strategy-protection 
capabilities of Condorcet and Smith//Condorcet have been vastly oversold.  I 
have seen no precise statements of such strategy-protection criteria on this 
list (maybe they were posted before I joined), and have seen no proofs of such 
criteria anywhere.  When I tried to formulate and prove similar criteria, I 
found severe weaknesses in this supposed protection.  I have not saying that 
such criteria could not be precisely stated and formally proven.  I'm just 
saying them I have seen no proofs at all, and that the statements of such 
criteria that I have seen had what I considered to be severe flaws.  I will 
attempt to post an example of such a flaw for the "lesser of two evils" 
criterion in the near future.

Second, but less important, Condorcet and Smith//Condorcet can be vulnerable to 
strategy manipulation in some cases when the methods I prefer (Regular-Champion, 
Consensus-Champion, Complete-Champion, and Qualified-Champion) are not.  This 
certainly does not mean that the methods I prefer are necessarily better, but it 
raises questions concerning exactly what are the meaningful properties that 
Condorcet and Smith//Condorcet really do possess.  I posted one example of this 
vulnerability already.  I'll post a second, closely related, example later 
tonight.

Third, and most important, Condorcet and Smith//Condorcet can select as winners 
what I believe the vast majority of voters (in economically developed countries) 
would think are incredibly ridiculous choices.  Such a selection may rarely 
happen, but if it happens even once in an election of any significance, it could 
set the single-winner reform movement back for decades, maybe even a century or 
two.  I don't think it's worth the risk for the minimal strategy protection that 
has been meaningfully demonstrated so far for Condorcet and Smith//Condorcet.  
Personally, I would feel quite comfortable defending any Regular-Champion (or 
Consensus-Champion, Complete-Champion, or Qualified-Champion) winner before a 
group of intelligent but hostile critics.  Conversely, I see no way of defending 
some of the winners that Condorcet and Smith//Condorcet can produce.  I will 
attempt to post relevant examples shortly.

Given the blatant losers that Condorcet and Smith//Condorcet can select as 
"winners," the choice between Condorcet and Smith//Condorcet and methods that 
cannot select such intuitive losers seems easy to me.  The harder question is to 
choose among those other methods.  In particular, choosing among  
Regular-Champion Consensus-Champion, Complete-Champion, Qualified-Champion, 
Qualified-Kemeny, Kemeny//Random, Niemi-Riker//Random, Smith//Borda//Random, and 
Smith//Bucklin-ext//Random is not so easy.  I based my choice on my which I felt 
was the simplest.

Bruce