Re: Fw: Voting project

From: Douglas W. Jones <jones_at_cs_dot_uiowa_dot_edu>
Date: Mon Aug 11 2003 - 16:49:03 CDT

On Monday, August 11, 2003, at 07:11 PM, Arnie Urken wrote:

> Matteo and Doug,
> "Preference" voting as you describe it is equivalent to "approval
> voting,"

That's what I'd intended to type, but it came out wrong. Sorry!

> Note that under approval voting, there can be plurality, majority, and
> unanimous ties...

IRV/STV can also produce ties if there are an even number of voters.
None of these schemes eliminate cliffhanger elections and ties! All
of them try to reduce the severity of the third-party spoiler effect.

In all of the ranked preference ballot counting schemes, there are
ways that a voter can try to use to take advantage of the fact that
some voters will not produce a total ranking of the candidates but will
only rank their first few choices.

With the weighted preference schemes, for example, if you know that
almost nobody will vote for Dr. Evil, throwing away your second-choice
vote by giving it to him allows you to give a 2-vote punch to your
first choice. If many people start doing this, though, it all evens
out, so you're taking advantage of the fact that most voters give their
honest rankings and as a result, that almost nobody will vote for Dr.

To play the system with STV/IRV counting, what you do is try force
extra rounds in the election, throwing away your first and second
choices, for example, by giving it to the schmucks you expect to be
eliminated in the early rounds. That done, you vote your real
preference in later rounds, hoping that the honest voters will only
give first and second choices and abstain in later rounds.

Both of these bits of strategic vote fiddling require that you have
excellent polling data up front so that you can predict how the vast
majority of voters will vote as you plan your own voting strategy
for maximal impact, and both of them lead to really bad results if
too many voters begin to play these games.

                                Doug Jones
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Received on Sun Aug 31 23:17:08 2003

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