[Election-Methods] [EM] Is "sincere" voting in Range suboptimal?
Abd ul-Rahman Lomax
abd at lomaxdesign.com
Wed Jul 25 11:40:44 PDT 2007
At 01:38 AM 7/25/2007, Chris Benham wrote:
Here is my analysis again of Abd's suggested 0-info 2-voter
3-candidate election, where our voter's sincere ratings ("utilities")
are A2, B1, CO :
Benham sent an image referenced to some site.... Yes, I could read
it, but... I can't take it apart to analyze it.
Below are the votes he presents; he starts by explaining:
>Only considering votes that both max-rate at least one and min-rate
>at least one, there are only 12 possible opposition ballots
>(3 that max-rate 2, 3 that min-rate 2, 6 that mid-rate 1).
He has eliminated the non-normalized style ballots. Given that we are
testing optimum strategy, and know nothing about the strategy of the
other voter, this is why he comes up with a different result than I.
I considered all opposing ballots to be equally likely.
Apparently, Benham believes that such votes would be rare. He may be
right. But this is not zero-knowledge, in fact, it is making
assumptions about voter behavior that actually does not match reality
*in some elections.* Further, we are *really* interested in the
many-voter case, which we can reduce to, effectively, a two-voter
case if our voter is coordinating and voting identically to exactly
half of the other voters. In this case, the opposing voters are
voting, effectively, with very high resolution Range, with our voter
block having only three choices: 0, 1, 2. (But multiplied so that the
voting power of the two groups is equal.)
In the many-voter case, any vote combination, among the votes which
can affect the result, is possible. And, in particular, they are
equally possible, if we take care to include every case evenly (which
is why 000 and 222 are both listed, though they have the same effect)
whereas Benham can argue in the two-voter case that 000 and 222 are
unlikely. That's debatable. What if the other voter is interested in
overall social utility and thus votes sincerely, without
normalization, which is known to maxmize utility better than
normalization? (Though, in this case, we really would want higher
resolution Range.)
The other voter may think, all these candidates are really middling,
so I'll vote 1, 1, 1. Yes, I'm abstaining from the result, but in a
more informative way than by not voting. We should also remember that
votes are usually taken in more than one election at a time, and
blank votes are *common* here, and there is some incidence of
overvotes where all candidates are marked. These are real
possibilities, and in some elections, might be equally common. (A
voter votes 000, it means, "I like none of these enough to vote
anything for them." Where such a vote is not moot, where, for
example, some further process would occur, this would be a not
uncommon result when there are only three candidates.
All this is really about the simple two-voter case; but those votes
that Benham does not consider here become very important in the
many-voter case, and they are, clearly, equally as likely, there, as
the other vote patterns.
>>There are, in the two-voter case, 27 possible ballots, being all
>>the base-3 numbers from 000 to 222. All are considered equally
>>likely, which simplifies the calculations by assigning the same
>>probability to each. In the many-voter, ballot-could-shift-result
>>election, the virtual ballots of 000 and 222 are, in fact and in
>>real elections equally probable with the others.
>
>I find that statement ridiculous, but of course including such
>essentially blank ballots can't change the ranking of the our three
>considered votes
I said "many-voter," i.e., there are 27 possible vote combinations,
also, with many voters, but they are presented a little differently,
and *very rare* other combinations are excluded. That is, for
example, the combination 000 is excluded because it's an exact
three-way tie with many voters, we might as well consider zero
probability for that. All of the vote combinations where there are
three candidates whose election the voter might effect with some vote
and some luck can be excluded, leaving us only with 3 pairwise sets
of 9 combinations each. And these are equally likely.
I'd suggest Benham look at this.
More information about the Election-Methods
mailing list