[EM] SODA

[Jameson Quinn]

2011/7/5 <fsimmons at pcc.edu>

> Jameson suggested that the SODA candidates make their approval decisions
> sequentially instead of
> simultaneously.
>
> The problem with this is that if a winning candidate moves to first place
> in the sequence by an increase
> in support, she may become a losing candidate:
>
> Assume sincere preferences are
>
> 35 A>B>C
> 34 B>C>A
> 31 C>A>B
>
> If approval decisions are made in descending order of faction size A, B, C,
> then B wins.
>
> If B gains more support so that the totals become
>
> 34 A>B>C
> 35 B>C>A
> 31 C>A>B,
>
> the sequential order becomes B, A, C, and the winner will be C.
>

No. B still wins. If A feels that C is winning, then A can delegate to B,
and then B cannot lose. So C cannot be the winner. And therefore B will
delegate to C, to force A's hand. Whether or not C delegates then is
irrelevant.

Of course, if A actually prefers C to B, and has managed to keep B ignorant
of this fact, then C will win. But then, in such a case, A could have gotten
the same result by being honest from the start.

>
>
> How can we fix this?
>
>
I don't think there's anything that needs fixing, though you may find
another example to show I'm wrong.


> How about allowing the largest faction (in this example 49 C) to go second,
> and making the second
> largest faction (in this example 27 A>B) go first?
>
> That would also work in the example above.  How bad would it be in a worst
> case example?
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