[EM] (no subject)

[Terry Bouricius]

Response to Warren... inserted below each of his points (marked by ***)

Terry Bouricius

----- Original Message ----- 
From: "Warren Smith" <warren.wds at gmail.com>
To: "election-methods" <election-methods at electorama.com>
Sent: Sunday, November 08, 2009 1:00 PM
Subject: [EM] (no subject)


>Terry Bouricius:
I'm not sure if it is quite at the layman level, but Prof. Nicloaus
Tideman's recent book "Collective Decisions and Voting" has an analysis of
vulnerability to strategic manipulation of virtually every single-winner
voting method that has ever been proposed and concludes that Range Voting
along with Borda and four other methods "have defects that are so serious
as to disqualify them from consideration." (page 238). Range Voting
advocates on this list dispute his definition of "resistance to strategy."
>A somewhat more accessible (and available online for free) analysis of
strategic vulnerability of various methods is in this doctoral paper by
James Green-Armytage ("Strategic voting and Strategic Nomination:
Comparing seven election methods"). He found that Range and Approval were
just about the worst in terms of manipulability.
http://econ.ucsb.edu/graduate/PhDResearch/electionstrategy10b.pdf

>REPLY BY WDS:
1.Tideman's book and the flaws in its (poor) notion of "resistance to
strategy" are discussed here:
http://rangevoting.org/TidemanRev.html

***
1. Tideman is quite careful and methodical in his analysis of resistance 
to strategy using real world election data as a basis for analysis. I 
agree, however, that his definition only covers a specific slice of 
strategy possibilities that his data allowed him to analyze, and he made 
no attempt to evaluate other kinds of possible startegy that Warren Smith 
and some others focus on. This does not mean Tideman's analysis is flawed, 
though it may be classified as incomplete.


>2. Bouricius forgot to mention, same way he usually forgets to
mention, that Tideman also found IRV to be "unsupportable."

*** 2. Warren Smith is wrong. He either hasn't read Tideman or is 
intentionally miss-representing Tideman here. On page 238 Tideman has a 
chart with five categories of summarizing his analysis of mehtods...
First is "Not supportable" whcih includes Borda, Range, Dodgson, Copeland, 
Coombs and Est. centrality.
The next category is "Arguably inferior to maxmin" which includes 
Condorcet, Simp. Dodgson, Nanson, Bucklin, Black, Young, and Wt. 
Condorcet.
The third categroy is "Supportable if ranking is infeasible" which 
includes Plurality, Approval, and Two-ballot majority.
The fourth category is "Supportable if a matrix is uncalculable" whcih 
includes only Alternative vote [IRV]
The last category is "Supportable if a matrix of majorities is calculable" 
which includes Maxmin, Ranked Pairs, Schulze, Alt. Scwartz and Alt. Smith.

     Warren is assuming that a matrix is always "calculable" and thus the 
supportable category that includes only IRV is in fact null. However, that 
is not what Tideman is arguing (or why would he create the category if it 
was always empty)? Elsewhere he discusses the practical limitations of 
voting methods used for public elections including ease of voter 
acceptance and argues that a hypothetical improvement of a system that 
requires complexities such as matrices may be impractical in large scale 
elections. He writes on page 240 "If it is feasible to require voters to 
rank options, then much more sophisticated processing is possible. 
However, it is conceivable that it would be feasible to require voters to 
rank options but not feasible to require vote-processors to produce a 
matrix of majorities. In this event the Alternative vote is supportable."

>3.Armytage's ideas & related ones are discussed in puzzle #112 here:
 http://rangevoting.org/PuzzlePage.html
(I actually managed to prove a number of things Armytage could not,
for example.)
However Bayesian Regret is the right yardstick and Armytage's (while
interesting) the wrong one.

***3. Warren Smith's conviction that Bayesian Regret is the gold standard 
for evaluating voting methods is not universally, nor even very widely 
held. It is a unique philosophical view held by those who subscribe to the 
Utilitarian philosphy, and is at least arguable. Many (most) people 
believe that when electing a single seat, the will of the majority should 
win out over the minority. This is necessarily rejected by the  believers 
in Bayesian Regret and advocates of Range voting.

-- 
Warren D. Smith
http://RangeVoting.org  <-- add your endorsement (by clicking
"endorse" as 1st step)
and
math.temple.edu/~wds/homepage/works.html
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