[EM] Why I prefer ranked-choice voting to approval voting
jeff.oneill at opavote.com
Sat Oct 15 05:42:39 PDT 2016
Hi Jameson, Ralph, Robert, and Michael,
I'm responding to all of your emails together though most of my comments
are responding to Jameson.
Second: I'm sorry, but I really can't bear the name "RCV" in a voting
> methods discussion. I know that's what IRV is frequently called in actual
> laws, but to me "ranked choice voting" is obviously the correct term for
> the whole class of voting methods which includes Condorcet, Borda, and IRV;
> not just for IRV alone.
I agree that the terminology is difficult and that RCV could and perhaps
should apply to any method where votes are ranked.
But there's an important, and predictable, class of election scenarios
> where it's strategically crucial NOT to rank your favorite first: center
> squeeze scenarios. If you have two candidates at ideological opposite
> points, with a third candidate in the middle near the median voter, it is
> actually quite common for the center to have the lowest first-choice
> support and get prematurely eliminated. This kind of thing happened in
> Burlington 2009; in multiple recent French elections; tragically, in Egypt
> 2011; and would have happened in the US 2000 if Nader had gotten over 25%.
> In this case, the correct strategy for one group of voters is to rank their
> true first choice in second place. Understanding this, and correctly seeing
> when it applies, is a HUGE cognitive burden for IRV voters.
When you say that "it is actually quite common for the center to have the
lowest first-choice support and get prematurely eliminated," we need to
clarify "quite common." If you mean 5-10% of the time, then I could
believe that, but if you mean 50% of the time, then I would disagree. It
would be really interesting if a statistician could collect the data and
I can't comment on Burlington or Egypt. For the French elections, the
center candidate is generally in the top three of 10-15 candidates
(depending on the year). Candidates that came later than that top 5 have
very little support.
My main point here, however, is that, except in rare situations, voters are
not capable of voting strategically to account for a center candidate out
of the top two (and by this I mean normal voters, not the people on this
list). First, it isn't clear how often the center candidate is out of the
top two. Second, voters would need to think deeply about how the voting
system works. third, you need precise polling information. Fourth, if you
are too successful in your strategic plan, it backfires. There is this
middle ground where enough voters have to vote strategically to get their
desired result but not so many that you overshoot and still elect the wrong
candidate. A few people (like the people on this list) may consider such a
scenario when voting, but I think it is far too complicated for any
significant subset of voters to consider it.
Second, IRV requires strict ranking. That's a nontrivial cognitive burden
> when there are more than a handful of candidates. If there were 15
> candidates in a race, how should a voter decide exactly which of them to
> give 8th preference? It's much easier to use absolute grades, as in
> Majority Judgment. (Behavioural research bears this out; strict ranking is
> harder than rating, for anything more than 3 or 4 options.)
This makes sense, but I don't think it matters so much. For most RCV
elections, nearly all ballots end up at one of their top 3 or 4 choices.
Rankings after this don't matter much. Also, if a person has trouble
deciding who to rank 7th and 8th, then perhaps the person doesn't have a
strong preference between them and would be equally happy (or more likely
equally unhappy) with either.
> On the other hand: is the strategic burden for approval voters actually
> that high? I think not. Consider the rule used by Ka-Ping Yee in his voting
> system visualizations <http://zesty.ca/voting/sim/>: a randomly-assigned
> strict threshold. This requires no strategic doublethink, yet leads to
> near-ideal outcomes under his assumptions. My point is that under approval
> sophisticated strategy is not nearly as important as under IRV.
Thanks for recommending this. I'll have to check this out.
But still, I think you have a point. Approval does have a cognitive burden,
> and we should account for that. That's precisely why I've been working on
> MAS (majority acceptable score) as an option: it's a simple 3-level voting
> system with an absolute minimum of cognitive burden. I believe that under
> MAS, in basically all everyday voting scenarios, a naive sincere ballot
> will be strategically optimal, or close enough to it that most voters
> wouldn't care.
I'll check that out too
> ps. You mention Condorcet, and argue that the strategic cognitive burden
> is higher than IRV. I disagree; but since Condorcet comes with a higher
> cognitive burden in just figuring out why a given candidate won, I agree
> that Condorcet methods are probably not best for large-scale elections.
I actually wrote "Condorcet voting has the same cognitive burden as
ranked-choice voting". So we agree on this, and I also agree with your
A quick response to Ralph: I agree that approval is great and even
preferable to RCV for some things, such as informal meetings. Even for
city council though, I would prefer a ranked vote.
Ralph and Robert also made comments about the cognitive burden of
understanding how the votes were counted. That is a different topic so I
don't want to get distracted from the main point I was trying to make.
Michael, sorry, but I couldn't follow most of your comments. I'm not a
regular reader of this email list, so I don't think I have the necessary
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