[EM] serious strategy problem in Condorcet, but not in IRV?

[Stephane Rouillon]

Dave Ketchum a écrit :

> <snip>
>       In Ranked Balloting:
>            I read above of "burying" - ranking a competitor at the bottom
> of the pack, BUT:
>                 If the competitor is that undesirable, this is normal voting.
>                 If this causes a less desirable competitor to win, this
> was self destructive deviousness, visiting deserved pain on those so dumb.

This can happen with plurality too in a three runners election...
Expected:
A: 34
B: 33
C: 32
D:   1
Reality:
A: 33
B: 30
C: 34
D:   1

Supposes I am a C>B>A fan.
If with a friend, we move our vote from C to B to block the expected election of A,

we could end up making A win!!!
Expected after "strategy":
A: 34
B: 35
C: 30
D:   1
Unexpected reality:
A: 33
B: 32
C: 32
D:   1

Classify strategies as much as you want, it is not their nature that is important.
It is their probability of occurence and their consequences.

Steph

>       <snip>