[EM] Approval Voting and Long-term effects of voting systems

[Jan Kok]

Thanks, Daniel, for starting a very interesting discussion on an important
topic!



On Sun, Nov 27, 2016 at 6:05 PM, Daniel LaLiberte <
daniel.laliberte at gmail.com> wrote:

>
>
> On Wed, Nov 23, 2016 at 10:58 AM, Michael Ossipoff <email9648742 at gmail.com
> > wrote:
>
> In EM discussion, and probably at the Center for Election Science too,
>> people have talked about why Approval will soon (if not immediately) home
>> in on the voter-median and then stay there.
>>
>
> I believe this is very significant, so I would like to see this
> discussion.  I'll go digging in the archives, unless someone has some
> references or summary pages.
>

Maybe this? From http://www.rangevoting.org/rangeVcond.html :

Could it be that Approval Voting is, in practice, more likely to produce
Condorcet Winners than "official" Condorcet methods?!

Counterintuitively, we can prove that under reasonable assumptions Approval
and Condorcet voting actually are *not* in conflict (no-conflict theorem
<http://www.rangevoting.org/AppCW.html>) and it is plausible that approval
voting will actually be *more likely* in practice to elect honest-voter
Condorcet winners, than "official" Condorcet methods!

And because strategic range voters generally vote approval-style, the same
would be true of range voting <http://www.rangevoting.org/RangeVoting.html>
elections with strategic voters. In other words:

   - To the extent range voters are *strategic* they will elect Condorcet
   winners (indeed quite likely doing so *better* than "official" Condorcet
   methods);
   - whereas to the extent they are *honest*, range voting should perform
   better <http://www.rangevoting.org/rangeVcond.html#slaves> than
   Condorcet.

Even if you don't quite buy all that, we think you still will agree that in
practice, one should expect no great advantage for Condorcet methods over
the simpler range voting system.


Also relevant to this discussion:

Candidate incentives under different voting systems, and the
self-reinforcing deterioration of US democracy
Warren D. Smith, January 18, 2005
http://rangevoting.org/WarrenSmithPages/homepage/candincent.pdf


I don't know if this message will go out to the EM list. There have been
some technical problems with the EM list in the last few months that have
prevented my posts from getting sent out.

- Jan
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