[EM] Highly-expressive preference voting

robert bristow-johnson rbj at audioimagination.com
Sun Aug 30 14:07:20 PDT 2015


On 8/29/15 9:24 PM, James Kislanko wrote:
> I cannot respond to what you describe, since it has no relevance to 
> what I said, which is there is no ranked ballot that can reproduce my 
> pairwise preferences if I use different criteria depending upon what 
> the pairs are.
>

i can't really decode this, James.

we all understand that with a population of voters, a Condorcet cycle 
can possibly result (Rock>Scissors, Scissors>Paper, Paper>Rock) and then 
you need to add something or have something more, in the tabulating 
criteria, to determine a winner.  (i actually think a cycle would be 
rare in real governmental elections using a ranked ballot.)  people on 
this list can argue which is best.  probably most agree that Schulze is 
best, but i think that if the cycle contains only 3 candidates, that 
Schulze and Ranked-Pairs (margins) and MinMax all pick the same winner.  
Ranked-Pairs is a helluva lot easier to explain to skeptical legislators 
and others i might try to convince to re-adopt the ranked ballot (but 
this time *not* to go with IRV), so i have been sticking with that.  
(and, as rare as a cycle might be, i think it would be even more rare 
for a cycle to have more than 3 candidates in it, so the difference 
between a Schulze and Ranked-Pairs might seem moot.)

but just because the collective vote totals might result in a circular 
preference, that doesn't mean that it's reasonable for a single voter 
to.  if a voter prefers Candidate Rock over Candidate Scissors and the 
same voter prefers Scissors over Paper, i cannot grok how this same 
voter could possibly prefer Paper over Rock.  then a single, linear, 
ranked ballot works fine in recording all of the contingency vote 
preferences of that voter.  the rest of the problem is taking all of 
this collection of ranked ballots, and with the principle of "One Person 
One Vote" determining what the collective preference of candidates is 
and identifying the winner.  outside of a cycle, i think that Condorcet 
works pretty well because, as long as there *is* a Condorcet Winner, 
that choice would prevail in any hypothetical one-on-one election and 
not the reverse.

people here since 2009 might remember when i joined the list and that i 
lived in a municipality with a strong 3rd party (the Progressive Party 
of Vermont), we had IRV for our mayoral election and, while a majority 
of voters marked their ballots that they preferred Candidate A (for 
Andy) over Candidate B (for Bob), nonetheless Candidate B was elected.  
a year later IRV was repealed, although a wide majority of voters didn't 
understand exactly what went wrong (and would dispute the problems), 
enough folks knew *something* was wrong and IRV and it was repealed and 
unfortunately along with it, the ranked-order ballot.

so, please elaborate on exactly what you mean.

r b-j

> On Saturday, August 29, 2015 4:46 PM, robert bristow-johnson 
> <rbj at audioimagination.com> wrote:
>
>
> On 8/29/15 6:17 PM, James Kislanko wrote:
> > This example is a perfect demonstration of what I tried to describe a
> > decade or so ago.There is no way to make a linear ordering of pairwise
> > preferences if the voter uses different criteria depending upon what
> > the pair is. I'd like my contribution to the pairwise matrix be based
> > upon a ballot that gave "A or B, neither?" for every combination of
> > choices.
>
> while IRV ballots seem to prohibit marking two candidates equally
> (except for those unmarked, who are all tied for last place preference
> on that particular ballot), there's nothing in a Condorcet ranked-ballot
> to stop you from marking A and B equally, whether they be first or last.
>
> how is
>
>   A = B = last place
>
>     any different an expression from "neither"?
>
> ranked ballot, in which tied ranking is allowed, is the most sensible
> form of expressive preference voting.  score voting requires too much
> "expression" from the voters and approval voting too little.




-- 

r b-j                  rbj at audioimagination.com

"Imagination is more important than knowledge."





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