[EM] IRV vs Plurality

[robert bristow-johnson]

On Jan 11, 2010, at 1:19 PM, Dave Ketchum wrote:

> On Jan 11, 2010, at 11:45 AM, robert bristow-johnson wrote:
>> On Jan 11, 2010, at 8:54 AM, Kathy Dopp wrote:
>>> ...
>>> Plurality is far better than IRV for many many reasons including:
>>>
>>> 1. preserves the right to cast a vote that always positively affects
>>> the chances of winning of the candidate one votes for
>>
>> and more often than not, *hurts* the credible candidate that is  
>> politically more aligned with the candidate one votes for.
>>
>> 50,000 voting for Nader elected W in 2000.  that is a matter of fact.
>
> Plurality does that only when you vote for one who has a  
> possibility of winning.

what do you mean.  Florida voters that voted for Nader (who had no  
chance of winning) were far more likely, if they would come to the  
polls at all, to vote for Gore over Bush if that was the choice  
presented to them.  *Gore* had a possibility of winning (and many say  
that he won, according to the law) and needed 530 more votes in  
Florida and the history of the first decade in the 21st century would  
have turned out far different.  there were thousands of Nader voters  
in Florida and the fact that the election was decided by plurality  
(and that W managed to prevent the rest of the Florida law from  
taking effect) meant that the secondary choice of the great majority  
of these Nader voters was harmed by their primary vote (and only  
vote) for Nader.

>   Sometimes doing that prevents voting for the one you prefer but  
> expect to lose.

yes.  sometimes that is the case and one must accept that he/she is  
in the minority.

>>> 2. allows all voters the right to participate in the final counting
>>> round in the case of top two runoff or primary/general elections
>>
>> but IRV does that in an instantaneous way UNLESS some voter  
>> changes their mind about their alternative candidate.  IRV or  
>> Condorcet (or any ranked ballot) requires the voter to choose  
>> *and* *commit* to not just their favorite, but their fallback  
>> candidate on the same Election Day.
>
> With Condorcet the voting is all done on one election day, and all  
> that the voters rank are considered in the counting.
>
> While the candidates and voters must do their preparation before  
> that one act of voting, that single voting round should be all that  
> is needed for the counting and deciding on winner.
>
> Note that primaries may be used, but there is no need for them such  
> as is true for plurality - multiple candidates for a party can be  
> voted for in a Condorcet general election, with voters ranking such  
> candidates if and when they choose.

but, between the lines here, the opponents of IRV (or any ranked- 
order ballot) want the Progs and Dems to together field a single  
candidate (like there would have to be a Prog/Dem nomination caucus  
at Burlington High School and *one* candidate comes out of that).   
that, in my opinion, is an insult to both the Progs and the Dems.   
they are different parties, they can field their own different  
candidates (or, if a single person is most preferred by Progs and  
Dems and is nominated by both town party caucuses, then that  
candidate can still just register once at City Hall).  (in New York  
state, a single candidate may run under multiple party banners and  
that state accumulates votes for that single person, even though they  
are cast under different columns.)   i dunno what Kathy Dopp thinks  
of NYS.

but, it doesn't matter.  even if the Prog and Dem are different  
candidates, the political alignment between the two parties is  
undeniable.  i believe that Burlington voters (and we'll see if this  
is still the case in March) do not want a minority GOP candidate to  
win solely because the liberals in Burlington split their vote.  the  
anti-IRVers insist that this is the price we must pay for having two  
separate liberal parties.

>>> 3. preserves voters' right to understandably verify the election
>>> outcomes because the counting is simple enough for them to do,
>>> precinct summable
>>
>> so does Condorcet.
>
> And Condorcet gives a more accurate view since the ballots more  
> completely state voters desires and all that they say gets counted.

the ranked-order ballot gets just the right information from the  
anonymous voter.  Approval and traditional FPTP do not ask enough  
questions and Range demands too much information from the voter.

the ranked ballot in IRV is not the problem with IRV.  it's the way  
IRV interprets the ballot info, counts the votes, and declares the  
winner that is the problem.

>>> 4. preserves the right for local precinct control of the counts  
>>> or in
>>> the case of election contests that cross county lines, local county
>>> control of the counting process
>>
>> so does Condorcet.    i like precinct summable too, but it isn't  
>> the end-all requirement for an honest election.
>>
>>> 5. is far less costly than the IRV counting process
>>
>> not in Burlington.  once the infrastructure was set up (the ballot  
>> scanning machines didn't have to be changed at all, the difference  
>> is that the precinct results (that had a record for how each  
>> ballot looked) were transferred to city hall and a computer did  
>> the rest.  because of FoI laws, this record is available for  
>> public scrutiny and has been scrutinized.
>
> Topic seems to be that a second look at a ballot is required in IRV  
> after it is determined that the top rank lost.  In Condorcet all  
> the looking is done in one pass.

well, no.  in Burlington the ballots are physically scanned once.   
the data for each individual ballot is parsed and re-examined for  
each IRV round.  for Condorcet, they would be scanned once and you  
*could* write the code to parse each ballot once and rack up pairwise  
totals for all candidate pairs, one ballot at a time.  but you also  
could parse the whole ballot data (all of the ballots) again and  
again for each candidate pair.  it's just a matter of how one likes  
to write their code, that wouldn't matter in any case.  the computer  
might not report results until all of the parsing is done (and it has  
the result), or it might do it as the parsing is done so some people  
can have some election-night excitement watching the totals increase  
(like watching a race).  but, for a town the size of Burlington VT  
(the largest town in the state, but VT ranks dead last in the size of  
the largest town in the state) it should take a second or two for a  
modern PC to do the whole thing no matter if it's one pass for the  
whole thing, or one pass for each candidate pair.

--

r b-j                  rbj at audioimagination.com

"Imagination is more important than knowledge."