[EM] Approval Voting vs Instant Runoff Voting

[Richard Moore]

LAYTON Craig wrote:

> Mike wrote:
>
> >In IRV, a CW can be favorite of more people than any other candidate is,
> >and still lose. That's a very plausible IRV scenario, and is likely
>
> As demonstrated, this can also happen in Approval.  The fact that it is
> somewhat less likely isn't particularly comforting.

The lower likelihood isn't what's supposed to be comforting. It's whether or
not the outcome happens for the right reasons. In IRV it's easy to have a
candidate win for the wrong reasons (as when voters' strategies backfire).

If the scenario happens under approval voting, I don't think that it happens
for the wrong reasons. The result happens because enough voters felt the
utility gap between their favorite candidate and their second favorite (or
their second and third, or whatever) was small enough to include that
additional choice, while the utility gap to their next choice was larger. In
other words, approval is tending to maximize voter utility.

 -- Richard