[EM] Range strategy pathological example (was Re: IRV vs Plurality)

[Jonathan Lundell]

On Jan 26, 2010, at 9:49 PM, Jameson Quinn wrote:

> I understand the limitations of my example. I still think it is a real weakness for Range - actually, the only real weakness. Range is still one of the best systems out there. But this is a reason to explore its weaknesses, not to ignore them - especially when these weaknesses are probably fixable.
> 

Two weaknesses, it seems to me, and I'm less sanguine about their fixability.

One is, as you suggest, the strategy problem. Range, and it's limit in one direction, approval, require the voter to make cast a strategic vote; there really isn't any such thing as a non-strategic range or approval ballot. But voters are privy to different amounts of variably useful information about other voters' preferences, and other voters' strategic choices in view of those (perceived) preferences, and so on ad infinitum.

The second problem kicks in with the suggestion that there *is* a sincere range ballot (not that any voter would cast it), namely some objective measure of utility, comparable from voter to voter. The idea that there's some objective (or at least intersubjective) common measure of cardinal utility is, deservedly, a fringe idea—at best—in social choice theory. 

I really don't see out either of these can be fixed.