[EM] What is the ideal election method for sincere voters?

[Juho]

On Mar 9, 2007, at 1:12 , David Cary wrote:

> I describe a sincere vote as one which reflects as accurately as
> possible the person's personal preferences.  The preferences are ones
> that are independent of the election method

Although the preferences may be independent of the election method  
the description of the method may have impact on how one votes. You  
discussed the Range vs. Approval case. In Approval voters could be  
requested/advised/recommended/guided 1) to mark candidates that they  
approve or 2) to mark one/some of the front runners and candidates  
that they prefer to these. Are both cases sincere according to your  
definition?

> , independent of
> information about how other voters will vote

My second approval "advice" above referred to the outcome of the  
election and the anticipated voting behaviour of other voters. So  
also that may have some impact.

It is also possible that a voter changes his sincere opinion of a  
candidate when he learns that that candidate has wide support. I'd  
say this is still sincere also in the "make your decisions without  
considering how your vote impacts the outcome of the election" sense.

> the different design intent / normative specification for range vs.
> approval voting.

The description of the methods and description of the behaviour of a  
voter are interesting.

In the approval case one could have the descriptions I mentioned  
above. One could claim that if one votes in line with the description  
one has voted sincerely. The second description of Approval assumes  
some "sincere strategic" thinking on which candidates are the front  
runners. The first description does not require the voter to think  
about how the method works and how other voters are going to vote  
(but it leaves space for "insincerely strategic" voters to vote more  
efficiently than those ones that voted as recommended.

In plurality corresponding recommendations are 1) to vote for the  
best candidate and 2) to vote for the best front runner. I guess most  
voters know that the second alternative brings better results to the  
voter in average even though they maybe consider the first one to be  
the "official definition".

In Range corresponding recommendations could be 1) to indicate one's  
level of preference for each candidate or 2) to vote as in approval  
(case 2) with max and min values, and with intermediate values if one  
wants to cast a "weak vote".

In Condorcet corresponding recommendations could be 1) to rank all  
candidates in the order of preference or 2) to check the guidance  
given by the experts of their party / candidate just before the  
election day. I wrote the second case intentionally vague since to  
this day I have not seen any clear generic guidelines on how to vote  
strategically in Condorcet elections. (Well, to be exact there is at  
least one quite generic strategy, to rank the (equally bad and  
equally strong) candidates of a competing party in the given order  
but starting from a random candidate and continuing from the  
beginning when the last candidate is reached. This way the  
probability of a loop among them increases.)

If the second definitions of the election methods are used, then the  
elections become more like games that all voters may play. A good  
strategy brings good results. My question is, when does "sincere  
voting" stop and when does "strategic voting" start in this scale?

Based on this discussion there could be some additional definitions  
that may be used in defining what sincere and strategic voting are:
a) if one votes as recommended, then one votes sincerely
b) if the description of the election method is complex and requires  
detailed analysis of the opinions of other voters and the candidate  
setting, then voting is strategic (even if in line with the  
recommended way of voting)
c) if the recommended way of voting approximates some agreed and well  
understood utility function, then voting in line with this  
recommendation is sincere
d) if one makes the decision on how to vote without considering how  
the vote impacts the outcome of the election in the vote calculation  
process, but based on some "external" values, then one votes sincerely

One could use also other terms like "intended style", "without  
analysis", "without complex analysis", "utility based voting".

Furthermore following points might apply
- not expressing one's opinion is insincere (e.g. truncation due to  
being too lazy to rank all the 100 candidates)
- defensive strategies are insincere (and of course strategic)  
(although the intention may be to achieve the result that sincere  
votes would give)
- buying votes and cheating is insincere (I mention this just to make  
the difference to heavy strategic considerations that are in line  
with the recommended way of voting)
- multiple sincere votes may exist when there are alternative equally  
good strategies

Sorry about not giving exact new definitions, but maybe you want to  
do that yourself :-).

Juho



		
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