[EM] Why the concept of "sincere" votes in Range is flawed.

Abd ul-Rahman Lomax abd at lomaxdesign.com
Mon Dec 1 17:01:51 PST 2008

At 01:52 AM 11/26/2008, Jonathan Lundell wrote:
>On Nov 25, 2008, at 8:45 PM, Kevin Venzke wrote:
>>--- En date de : Mar 25.11.08, Abd ul-Rahman 
>>Lomax <abd at lomaxdesign.com > a écrit :
>>>What Approval sincerely represents from a voter is a
>>>*decision* as to where to place an Approval cutoff.
>>But is it not true that what *all* methods sincerely represent from a
>>voter are the decisions related to voting under that method?
>>If a decision makes sense in a given context, then that is a sincere
>>decision. Is that not your stance?
>It shouldn't be. "Sincere" is a term of art in this context, not a
>value judgement. An insincere vote is simply one that does not
>represent the preference of the voter if the voter were a dictator.
>There's nothing *wrong* with voting insincerely (or, equivalently,
>strategically), in this sense; a voter has a right to do their best to
>achieve an optimum result in a particular context. ----
>Election-Methods mailing list - see http://electorama.com/em for list info

That is more or less correct, except that 
"sincere" may refer to any vote that doesn't 
reverse preference. Again, Mr. Lundell is right, 
there is nothing wrong with voting in a manner 
that is intended to improve the outcome as the 
voter sees it. A decent method will not be 
*seriously* harmed by this behavior. A poor method may actually be improved.

This should be explored explicitly.

With poor voting systems, strategic voting not 
only improves the outcome for the individual 
voter, but it also may improve it for the overall 
society. Consider Florida 2000. Many of us might 
think that the outcome would have been better if 
the Nader supporters had voted "strategically." 
Plurality needs that kind of help to find a 
compromise winner better than the first 
preference winner. So might IRV -- though it 
needs it less. Favorite Betrayal is a means 
whereby some voters in IRV, by voting 
insincerely, can improve the overall outcome for a majority of voters.

But when a system is really good, like Range, 
strategic voting impairs the ability of the 
system to find the optimal winner. However, the 
failure isn't catastrophic, because the Range 
Votes still preserve preference order; they are 
essentially Approval votes. So "strategic Range" 
degrades to Approval, not to some major failure. 
Approval, likewise, degrades to Plurality under 
some circumstances, but these would be poor 
strategy, applied by too many voters.

(The majority of voters under Approval, in most 
elections, may bullet vote, it's sincere and if 
it is for a frontrunner, it's optimal or 
almost-optimal. It is only a few voters who need 
to add additional approvals. Under some 
definitions of sincere voting -- the ones used by 
critics of Approval, these are possibly 
"insincere" because the voter is suppressing 
their preference, the minor candidate who can't 
win, in order to cast a vote in the meaningful 
election, i.e., the only pairwise election -- 
normally -- where a vote has a chance of being 
other than moot. But I wouldn't call those votes 
insincere, they merely do not express a 
preference in a candidate pair, but sincerely 
express preference for the pair -- either of both 
members -- over all other candidates.)

That "strategic voting" harms results in Range is 
then misused by critics as a criticism of Range. 
In fact, Range with strategic voting does not 
degrade to the point that it is not better than 
other methods. Obviously, if all voters vote 
using Approval strategy -- which doesn't really 
improve expected results for many of them -- the 
method has fully degraded to Approval. Which is 
still an excellent method, with lower average 
regret in the simulations than Plurality or IRV.

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