[EM] A very hard to manipulate random SPE method?

[Daniel Carrera]

On Sat, Jan 29, 2022 at 7:35 AM Kristofer Munsterhjelm <km_elmet at t-online.de>
wrote:

> Here's an idea for an SPE method that should be pretty hard to
> manipulate. It can only be done interactively.
>
> First, the moderator chooses two candidates at random. The group votes
> pairwise between the two. Like in SPE, the winner of the two is
> retained. Then the moderator repeatedly chooses an unevaluated candidate
> at random, pairs the current champion with the challenger, and whoever
> wins pairwise goes on to the next round. The last candidate standing is
> the winner
>
> So basically it's SPE with a random candidate order, except that the
> order is not fixed in advance. That it's not should make it harder still
> to manipulate because it's far from obvious who a candidate should be
> buried under in order for the burial to succeed.
>
> For instance, suppose A and C are called. B>A voters know that A has
> good support so they would like to bury A to create a cycle where B
> wins. But they don't know if the future agenda order is set up so that
> burying under C will make some loathed candidate D win.
>

Up to this point, would the system work the same way if the order was set
by a pseudo-random number generator? You could use properties of the
ballots cast as a source of entropy.


It's not cloneproof since it uses Random Candidate instead of Random
> Ballot. A better version would use Random Ballot, but it would be harder
> to do so interactively - to pick a random voter and ask for that voter's
> favorite among the unevaluated candidates.
>
> And obviously there should be great security around the entropy source
> so that the moderator can't control the agenda.
>

In the interactive version, I wonder what would happen if the losing
candidate gets to pick the next candidate. I'm hoping that that could make
the strategy complex enough to be impractical.

Cheers,
-- 
Dr. Daniel Carrera
Postdoctoral Research Associate
Iowa State University
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