[EM] Anyone got a good analysis on limitations of approval and range voting?

[robert bristow-johnson]

On Nov 7, 2009, at 3:12 PM, Matthew Welland wrote:

> It seems to me that approval and range voting eliminate most of the
> strategic opportunity in single winner elections and the marginal
> improvement of other methods is fairly small. Can anyone point me to
> analysis, preferably at a layman level, that contradicts or  
> supports this
> assertion?
>
> Or, in succinct terms, what are the strategic flaws in approval or  
> range
> voting?

this is no published analysis, but it should qualify as layman  
level.  this is why i don't like either approval or range voting in a  
governmental election.

in a sentence: Approval Voting does not collect enough information  
from voters and Range Voting requires too much.

since any of these methods we discuss here really exist for the  
purpose of dealing with more than two candidates (if there are  
exactly two candidates no one really disagrees about what to do)  
let's see if we have to do with multiple candidates.  in fact we can  
use the 2009 mayoral election in Burlington VT as an object lesson.

we have Candidate A (we'll call "Andy"), Candidate B (we'll call  
"Bob"), Candidate C (we'll call "Curtis", but in Burlington his name  
was Kurt), and candidate D (we'll call Dan).

Approval Voting: so i approve of Andy and Bob, maybe Dan (not likely)  
and definitely not Kurt (err "Curtis", candidate C).  but, if the  
election comes down to Andy vs. Bob, i want to register my preference  
for Andy.  how do i do that?  so then i'm thinking (tactically) that  
the Bob supporters aren't gonna be reciprocating with an approval  
vote for Andy, so what do i do if i really support Andy, am willing  
to settle for Bob, but really want Andy.  i will agonize over the  
decision and likely just vote approval for Andy, just like i would in  
a traditional FPTP election.  but then there is no information coming  
from me that i prefer Bob a helluva lot more than i approve of  
Curtis.  so Approval Voting has not relieved me, as a voter, from the  
need to consider tactics, if i want my vote to be effective.

Range Voting:  so i have 100 points that i can distribute among the 4  
candidates.  well definitely Candidate C ("Curtis", really Kurt) gets  
zero of my points.  i might toss Dan 5 points, but i would likely not  
waste them.  so how do i divide my points between Andy and Bob?  i  
like them both, but prefer Andy over Bob, so what do i do?  i have to  
think tactically again.  are the Bob supporters gonna be tossing any  
points to Andy?  i can't trust that they will, they will probably  
just put all of their support for the candidate that they are  
behind.  if i want my vote to compete effectively with theirs, i will  
end up putting all 100 points behind my candidate Andy.  so, if we  
have any political identification at all, my vote under Range will  
convey no more information than it would with FPTP.

IRV, Condorcet, and Borda, use the simple ranked-order ballot where  
we say who we support first (candidate A for me), who is our second  
choice (candidate B), who is our third choice (candidate D for me)  
and who is our last choice (candidate C for me).  so if the election  
was just between A and B, we know that this voter (me) would vote for  
A.  if the election was just between B and D, we know this voter  
would vote for B.  if the election was between C and D, we know this  
voter would choose D.  of course, for a single voter (not necessarily  
for the aggregation of votes) there is no circular preference, we  
know that if the election was between A and D, this voter would vote  
for A.  we know that this voter would vote for B if the election was  
between B and C.  and we know that this voter would vote for A if it  
were between A and C.  from that simple ranked-order ballot, we know  
how the voter would vote between any selected pair of candidates in  
the hypothetical two-candidate election between those two.

of course IRV, Condorcet, and Borda use different methods to tabulate  
the votes and select the winner and my opinion is that IRV ("asset  
voting", i might call it "commodity voting": your vote is a  
"commodity" that you transfer according to your preferences) is a  
kabuki dance of transferred votes.  and there is an *arbitrary*  
evaluation in the elimination of candidates in the IRV rounds: 2nd- 
choice votes don't count for shit in deciding who to eliminate (who  
decided that?  2nd-choice votes are as good as last-choice?  under  
what meaningful and consistent philosophy was that decided?), then  
when your candidate is eliminated your 2nd-choice vote counts as much  
as your 1st-choice.

i don't like Borda because it has another arbitrary valuation.  the  
difference in score between your 1st and 2nd choice is the same as  
the difference in score between your 2nd and 3rd choice.  but what  
eternal value is that based on?  what if i like my 1st and 2nd choice  
almost equally, but think my 3rd choice is a piece of crap?  (this is  
what Range Voting is trying to solve by *asking* me what the  
difference is, but as i wrote above, Range Voting makes me consider  
tactics and i'll likely just put all of my marbles under the  
candidate of my choice, so as not to harm him if he ends up  
ultimately competing against my second choice.)

that leaves Condorcet, for me.  and the reason to elect the Condorcet  
winner is simply that this candidate is preferred to every other  
candidate when the elecorate is asked to choose between the two.  or  
stated negatively, if a Condorcet winner exists and the Condorcet  
winner was not elected (by whatever rules, like IRV's kabuki dance)  
then your election authority just elected a candidate when a majority  
of voters marked their ballots explicitly that they preferred a  
different *specific* candidate.  in a democracy, why should we elect  
someone when more of us prefers someone else?  that makes no sense.

this actually happened in Burlington Vermont in 2009.  and, again, if  
someone wants to read a paper i wrote (to Burlingtonians) about what  
happened (with IRV) and why we should change it, i'll email you a copy.

my $0.02 .

--

r b-j                  rbj at audioimagination.com

"Imagination is more important than knowledge."