[EM] Looking at Condorcet

robert bristow-johnson rbj at audioimagination.com
Wed Feb 1 20:45:04 PST 2012

On 2/1/12 10:22 PM, Dave Ketchum wrote:
> Mike offers serious thinking about Approval.  I step up to Condorcet 
> as being better and nearly as simple for the voter.
> Voter can vote as in:
> .     FPTP, ranking the single candidate liked best, and treating all 
> others as equally liked less or disliked.
> .     Approval, ranking those equally liked best, and treating all 
> others as equally liked less or disliked.
> .     IRV, giving each voted for a different rank, with higher ranks 
> for those liked best, and realizing that IRV vote counters would read 
> only as many of the higher rankings as needed to make their decisions.
> .     Condorcet, ranking the one or more liked, using higher ranks for 
> those liked best, and ranking equally when more than one are liked 
> equally.
> Condorcet is little, if any, more difficult for voters than FPTP and 
> Approval.
> .     For many elections, voting as with them is good and as easy.
> ..     When a voter likes A and B but prefers A - Approval cannot say 
> this, but it is trivial to vote with Condorcet's ranking.

Condorcet is *simpler* to define than IRV or Bucklin (maybe not simpler 
than Borda, but Borda sucks).  here it is:

"If a majority of voters agree that Candidate A is a better choice than 
Candidate B, then Candidate B is not elected."


"If Candidate Bob should be elected mayor, then Candidate Bob should be 
preferred by voters to Candidate Andy.  And Candidate Bob should be 
preferred by voters to Candidate Kurt.  And Candidate Bob should be 
preferred by voters to Candidate Dan.  And every other candidate."

THAT IT!  who can argue with that?  If any voters wonder what the 
meaning of their ballot is, it is simply that if they rank Andy above 
Bob above Kurt above Dan, all that means is that if the choice was 
between Andy and Bob, they pick Andy.  If the choice is between Bob and 
Kurt, they pick Bob.  And if the choice is between Andy and Kurt, they 
pick Andy.  (the same as with IRV or Bucklin or Borda.  that's all the 
ranked ballot means.  it means that we require the voters to make up 
their minds about the candidates by Election Day, and it's hard for me 
to understand why that is such a hardship.)

what else need there be to it?  there is nothing more to it.

it doesn't say anything about how much more they like Andy over Kurt 
than they like Andy over Bob, except it must be at least a little more 
because they prefer Bob to Kurt.  but it could be a lot more.  however 
it doesn't make any difference.  this voters vote counts *equally* as 
much in the contest between Bob and Kurt as it would in the contest 
between Andy and Kurt.  it's ONE-PERSON-ONE-VOTE in either case, and i 
do not see it quite so with Range/Score.  that is what is wrong with 
Range.  why i see it dead on the track right outa the blocks.

> In Condorcet the counters consider each pair of candidates as 
> competing with each other.  Usually one candidate, being best liked, 
> proves this by winning in every one of its pairs.  Unlike IRV (which 
> requires going back to the ballots as part of the counting), counting 
> here can be done in multiple batches of votes, and the data from the 
> batches summed into one summary batch for analysis.
> There can be cycles in Condorcet, such as A>B, B>C, and C>A, with 
> these winning against all others.  This requires a closer look to 
> decide on the true winner, normally one of the cycle members.
> .     Here the counters see the cycle, rather than a CW - and how to 
> pick a winner from a cycle is a reason for the dispute as to what is 
> best.

i still have seen *no* convincing evidence that Condorcet cycles would 
be common.  but, just in case, there should be language in the law (if 
Condorcet is ever adopted) to deal with cycles, so that the election is 
decisive (and no delayed runoff with only a fraction of the voters 
showing up).

and it's even far less unlikely that if a Condorcet cycle *did* occur in 
a governmental election that there would be more than 3 candidates 
involved in the cycle.  then in that case, Schulze, Minmax, or Ranked 
Pairs (margins) all agree who the winner is.  sounds to me that the 
simplest language should be used, which, to me, appears to be Minmax or 
RP (sorry Markus).  i think i like RP better than Minmax, but i dunno.

> Range/score ratings have their own way of showing more/less desire.  
> Truly more power than Condorcet ranking

it's no more *power*.  it is more *expressivity* but also more of a 
burden.  how high do you score your 2nd choice so that all of your 
electoral muscle helps the 2nd choice beat lower choices but none of 
your effort helps the 2nd choice beat your 1st choice?  that's a tough 
question and places upon the voter a burden of tactical voting.

Approval has a similar problem.  do you Approve of your 2nd choice or 
not?  do you want to help your 1st choice beat your 2nd choice, or do 
you want to help your 2nd choice beat your lower choices.  you cannot do 
both in Approval voting and the voter has to make an agonizing choice if 
the 2nd choice was ever worthy of approval.

> - AND more difficult to decide on rating values to best interact with 
> what other voters may do.

that's what i've been harping about here since 2009.  i know some of the 
folks are here, but this Range/Score and Approval thing has made no 
progress with me.  i think, just by virtue of the ballot and what it 
asks of voters, are flawed systems from the start.

sorry, Warren.

maybe Range ain't so bad for Olympic judges, but when we go into a 
voting booth, we ain't exactly judges.  we're *partisans* and i want to 
make my vote count as much as it can to elect my favorite candidate (and 
i want no others vote to count more than mine).  and, if my favorite 
candidate just cannot win, i want my contingency vote to count as much 
as it can to elect my next favorite candidate (and i want no others vote 
to count more than mine).  this is why Range does not cut it, for 
governmental elections.


r b-j                  rbj at audioimagination.com

"Imagination is more important than knowledge."

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