[EM] Why I think IRV isn't a serious alternative

[Abd ul-Rahman Lomax]

At 12:54 AM 11/26/2008, Dave Ketchum wrote:

>>My own view is first that we're talking about marginal differences
>>here, and that PR vs single-winner elections is of much, much greater
>>interest, and second that the interesting difference 
>>between  plurality, IRV and other ranked methods is not in how they 
>>count any  particular profile, but rather in how they influence 
>>candidate and  voter behavior. In the IRV examples that Greg and 
>>Abd adduce, we don't  actually know what the ballots would have 
>>looked like if the elections  had used plurality. The set of 
>>candidates might well have been  different, the nature of the 
>>campaigns different, and voter strategies  different.

That's correct. We can make some reasonable assumptions, though. We 
can look at Plurality elections and look at how many voters vote for 
minor candidates with no hope of winning. We can then look at IRV 
results and convert comparable percentages of these votes to 
plurality votes for frontrunners. I think we could get pretty close.

Campaigns, from experience, don't seem to be much different. Voter 
turnout doesn't seem to be much improved with IRV, though, 
theoretically, it should improve turnout a little. The fact, however, 
that the sincere preferences expressed by voters for minor candidates 
don't shift results, in nearly all cases, acts contrary to this 
effect, in the long run. So you get to vote "sincerely," but with no 
net effect? You can "vote" more sincerely by giving a campaign 
donation to a minor candidate!

Voter strategies in Plurality are based on main considerations:

(1) Vote for the favorite. This actually works, it's better than one 
might think. It is *highly* likely to produce the same winner as a 
more advanced method, and it is only under special conditions that it 
fails. So a lot of voters do this. Note that, by definition, most 
voters, voting this way, are voting for a frontrunner, so this 
"sincere" strategy is the same as consideration 2.

(2) Vote for the preferred frontrunner, because all other votes are 
moot. This is only important for minor party supporters who want to 
express that for some other purpose than winning an election, such as 
ballot position. Or for purely personal reasons, such as being pissed 
at a party for not nominating their favorite, who is running, and 
they either think that the possibility of the candidate from the 
opposing part won't win in any case, or they don't care. Damn them 
all! Yes, some voters vote like this, God bless them. It's part of 
the system. Don't unnecessarily piss people off, make sure they see 
the process as fair, if possible. Not always possible.

Which of these strategies the voter actually uses depends on 
preference strength. Tricky to estimate, but, again, I think that by 
studying average behavior, we could get close.

Essentially, we can look at IRV results and predict, probably within 
a few percent, what the Plurality vote would have been. Most voters 
probably use strategy 2 in Plurality; Plurality also tends to 
suppress minor party candidacies which, with Plurality, show far 
lower than the real party support, because of the strategic voting. 
One of the benefits of Range, Warren calls it the "incubator effect," 
is that a measure of third party support becomes available, and there 
is little reason to assume that this would be insincere. Why bother 
voting an "insincere" rating for a non-viable candidate? Given that 
the vote has about zero chance of influencing the outcome, in most elections.

(But if you prefer a major candidate, it could be foolish, with 
Range, to max rate a minor candidate. It doesn't accurately represent 
your preferences, but for no good strategic purpose. Only if you fear 
that the minor candidate might be the runner-up, and lose to someone 
worse, would you do that, and this means that you don't think this is 
a minor candidate. This might be a winner. I've said this many times: 
if you would seriously regret a Range Vote, under any reasonable 
scenario, including some election surprise -- like Le Pen getting 
second place -- don't vote that way. Adjust your vote so it is safer. 
The Le Pen result was not expected, to be sure, but those French 
elections, with many candidates, were very susceptible to small 
variations. Had it been a Range election in the primary, Le Pen 
wouldn't have made it to the runoff, I'm sure. *Maybe* Range would 
have detected Jospin, maybe not. With "sincere" Range votes, sure. 
But the Range winner, with no runoff, would almost certainly have 
been Jospin. Note that IRV could easily have missed Jospin, for the 
same reason that the plurality primary missed him. Jospin would have, 
with even higher certainty, in a majority -required Range election, 
been in a runoff against, again with high certainty, with Chirac, and 
would have won.)

(FairVote, to criticize Range, posits a truly preposterous election 
scenario, where voters prefer one candidate over another, and 99% 
vote 100 for the favorite and 99 for the other. A very small set of 
voters (1 or 1% in the example) vote 0 for the first and 100 for the 
second, and, of course, this outweighs the preference of a huge 
majority. But it is an extraordinarily weak preference, and if it was 
accurate, all voters will be very satisfied with this outcome, and 
they will not be saying "damn! I wish I'd voted like that selfish 
voter!" They will be, instead, if this is a real election, and there 
were other candidates who might have won, with significantly lower 
preference, very happy with the outcome and they will all go out and 
party together. In other words, FairVote wants us to think that the 
violation of the Majority Criterion is a Bad Thing, when, in fact, 
the outcome is very good, better than I have *ever* seen in a public 
election. If that majority would regret its supposedly "sincere" 
vote, why in the world did they vote that way, effectively abstaining 
from an important pairwise election. Surely the exaggerated their 
real preference toward the top. That is an error in voting, and 
errors in voting can always produce poor results! In a real election, 
how likely is this error?)

(We have 99% of the voters apparently thinking that there is a risk 
that their favorite will lose, not to the second candidate, the 99, 
but to someone much worse. However, in fact, there are *no* voters 
who prefer the third candidate. If there is no third candidate -- 
FairVote doesn't specify -- then what we have is a situation where 
the 99% majority essentially said, well, we have a tiny preference 
for one candidate, but, really, don't listen to us unless the rest of 
you really don't care. So they voted with votes of 1/100 vote value 
in a binary election. Why? Only if they really don't care, this is 
*almost* like a voter abstaining. Indeed, it's an almost total 
abstention on the part of the voters. This vote is based on the idea 
that voters are supposed to vote sincere absolute utilities, though 
in this case, the utilities were normalized at the top but not at the 
bottom. So the 99% may have been saying, I have a *significant* 
preference for A over B, but because both A and B are not Genghis 
Khan or Adolf Hitler, I'd have to be pretty grateful for the election 
of either, so, to be honest with you, my preference for A over B is 
only 1% -- tiny -- of my preference for B over C. I'd die to prevent 
C from being elected. C isn't on the ballot? That's irrelevant, I'm 
voting my "sincere utilities" because someone told me this was 
better. And if they believed that, I can get rich, I can sell them 
deeds to famous bridges. Voting is a choice, not a sentiment. If this 
is a binary election, you are being asked to make a "sincere choice," 
not make a "sincere rating." You can rate "sincerely" if want, but if 
you don't want to waste your vote, you will have to normalize your 
vote to the candidate set at the bottom, too. Which would imply 
voting min for B, if there are only two candidate. Voters *can* vote 
as described, but, then, it *clearly* is based on a desire to 
abstain. These are votes, expressed in fractions of a vote, multiples 
of 1/100 vote, they are *not* sentiments. If you care about the 
outcome, show it!)