[EM] Absolutely new here
jameson.quinn at gmail.com
Sun Jun 16 08:19:45 PDT 2013
As one of the principal advocates for Bucklin systems on this list, I
thought I'd expand a bit on Kristofer's excellent response.
2013/6/16 Kristofer Munsterhjelm <km_elmet at lavabit.com>
> On 06/16/2013 05:26 AM, Benjamin Grant wrote:
>> [...IRV discussion...]
> [...good response...]
> 2)I haven’t seen a voting system like this – what are the issues with
>> it? Upsides and downsides?
>> A)Each voter ranks their choices on their ballots, first through last
>> B)If one candidate got a majority of 1^st place votes, they win. If not,
>> the second place votes are added. If still no majority he third place
>> votes are added, and so on, until one candidate has a majority.
>> Would the above system work?
> That's Bucklin. http://en.wikipedia.org/wiki/**Bucklin_voting<http://en.wikipedia.org/wiki/Bucklin_voting>. It's one of the few ranked methods that have been used in political
> elections in the United States, and it has a connection to median rating
> (which elects the candidate with highest median rating or grade).
> It would work, but the rating variant is better. In the context of
> ranking, Bucklin fails Condorcet, for instance.
In case it wasn't clear, by "rating", Kristofer means a system with a fixed
number of levels of support/opposition (typically 3-7), where voters can
any number (including 0) of candidates at a given level. Ranking means that
voters must give a strict ordering of candidates, with no ties or skipped
> It also has some bullet-voting incentive.
In this case, "It" refers to the ranked version only.
> Say that you support candidate A. You're reasonably sure it will get quite
> a number of second-place votes. Then even though you might prefer B to A,
> it's strategically an advantage to rank A first, because then the method
> will detect a majority for A sooner.
> One of the points of the graded/rated variants is to encourage the voters
> to think in absolute terms ("is this candidate good enough to deserve an
> A") rather than relative terms ("is this candidate better than that
> candidate"). If they do, then the method becomes more robust.
One think Kristofer didn't mention is that your definition wasn't quite
complete. What happens if two candidates attain a majority at the same
rank, or (in rated versions or due to truncation) no candidate attains a
majority without including the bottom support level? Resolving this issue
requires a Bucklin completion method, just as resolving cyclical
preferences in Condorcet requires a Condorcet completion method.
Colloquially, Bucklin completion methods are often called "Bucklin
Thus, there are many possible Bucklin systems, including "ER-Bucklin"
(which majority is highest?), "Majority Judgment" (remove an equal number
of ballots at the pivotal/median rating for each candidate until one of
them gets a majority at a higher or lower rating), "Graduated Majority
Judgment" (find the candidate who needs the lowest percentage of their
ballots at the pivotal/median rating to attain a majority; also expressable
as a simple algebraic formula that gives a non-integer score to each
candidate), and the as-yet-unnamed method currently being discussed (for
the candidate with the greatest number of above-median votes). I'd
appreciate it if you read the posts linked above and responded with your
own opinion as to naming.
Supporters of Bucklin methods (like me) typically speak of the following
- Voters can express, and the system can respond to, varying levels of
support. Score voting (aka Range voting) is even better in this regard, but
Bucklin systems are still better than most others.
- In many cases, an "honest" (scaled utility) vote is strategically
optimal. For instance, say the rating categories were the letter grades
A-F, and the two frontrunner candidates both had a median of "C". A voter
who had given one of those two a "B" and the other one a "D" would have
cast a full-power vote, and would not need to regret not having given those
candidates an "A" and an "F". This contrasts with Score Voting, where in
general only approval-style votes (all top- and bottom-rating) are
strategically optimal. The hope is that by leaving more room for honest
voting, Bucklin systems will get better information from voters, allowing a
Welcome to the list, and we hope to hear more from you,
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