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

Abd ul-Rahman Lomax abd at lomaxdesign.com
Sun Dec 21 23:21:41 PST 2008

At 04:31 AM 12/21/2008, Kristofer Munsterhjelm wrote:
>In any case, it may be possible to have one of the LNHs and be 
>monotonic and have mutual majority. I'm not sure, but perhaps 
>(doesn't one of DAC or DSC do this?). If so, it would be possible to 
>see (at least) whether people strategize in the direction of early 
>truncation by looking at methods that fail LNHarm but pass LNHelp; 
>that is, Bucklin. Was bullet voting pervasive under Bucklin?

In some contexts, yes. However, we see upwards of 30% or so usage of 
additional preferences in the municipal elections I've looked at. I 
consider that high. Bullet voting occurs for reasons other than LNH 
concern. As Lewis Carroll pointed out, it's simply how many people 
will vote, representing their best knowledge, they may not have 
sufficient knowledge to intelligently rank or rate the rest of the 
candidates. Further, if they have strong preference for their 
favorite over all others, they may not care to vote for any of the 
others, not wanting to contribute to the victory of any of them. 
Voting is a moral action, and choosing the lesser of two evils isn't 
always the best thing to do. Sometimes the best action is to reject 
both evils, and that's what a bullet vote for the best candidate 
could be doing.

In other words, Nader supporters in 2000, if they really believed 
that Gore and Bush were Tweedledum and Tweedledee, might not have 
added an additional ranked choice for Gore even if the method had 
allowed it, and LNH has nothing to do with that.

We don't know, unless we do some serious ballot analysis -- the 
necessary information is available from a few elections now -- how 
many IRV voters truncate, because we don't know the lower preference 
expressions from those who did vote for a frontrunner. My guess is 
that the numbers are quite similar to what I've seen with Bucklin 
historically and what I'd expect from Bucklin today.

>We can stil get some idea of how easily voters would strategize by 
>looking at Bucklin, though; or for that matter, at ranked voting 
>methods that fail both LNHs. Schulze's used in some technical 
>associations (Debian, Wikimedia), and, although I don't have raw 
>voting data, they seem to be mostly honest. The Wikimedia election 
>had no Condorcet cycles down to the sixth place, for instance.

What I've seen from Bucklin, there is a very extensive analysis of 
the Cleveland election of 1915, I think it was, is that voters who 
didn't want to vote for a candidate didn't. Truncation, at least in 
Bucklin, is not insincere! All things considered, the numbers of 
additional preference votes are actually higher than I'd have 
expected. FairVote claims additional preference votes on the order of 
11% in a series of Alabama party primary elections, and that majority 
failure was universal. I'm not sure what to make of that, beyond a 
possibility that most primary voters simply knew who their favorite 
was and trusted that the plurality favorite would be good enough. In 
nonpartisan elections, it seems, regardless of theory, the first 
preference leader wins the election, exceptions have to be pretty 
rare. (None so far in the U.S. with well over thirty such elections.)

11% additional preference will flip some elections, and apparently it 
did. Indeed, some of the opposition to Bucklin seems to have come 
from parties and candidates who lost elections due to additional 
preference votes, considering that this somehow violated their basic 
right to win if they get the most first preference votes.

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