[EM] RCV Challenge

Kristofer Munsterhjelm km_elmet at t-online.de
Tue Dec 28 01:55:43 PST 2021

On 28.12.2021 06:56, Forest Simmons wrote:
> Robert,
> You wrote ...
> "I'm just a Condorcet guy.  How cycles get resolved is less motivating
> to me than insuring that the Condorcet winner is always elected"
> But "how cycles get resolved" has a big influence on whether or not they
> come into existence.  And when these cycles are created, the sincere
> Condorcet Winner goes out the window ... no longer showing up as a
> "beats-all" candidate on the ballot set. Can the cycle resolution method
> reconstruct the lost CW? All bets are off.
> The easier it is to game the cycle resolution method, the more incentive
> for the gamers to create the cycles.
> It seems that most Condorcet cycles are artificially created.
> For example, one way to create a cycle is by an insincere rank reversal
> technique called "burial". 
> If the cycle resolution method has no built in disincentive/negative
> feedback for this (or any other) kind of cycle creation, over time the
> gamers find out that they can manipulate elections to their advantage
> with impunity, so that artificially created cycles become more and more
> common, giving the false impression that cycles are a normal fact of nature.

There's still a question of just how much coordinated strategy will
happen. If the voters are mostly honest, then insisting on strategic
resistance will only be giving up honest performance for nothing
important in return. On the other hand, something like Borda obviously
collapses because it can't handle *any* kind of strategy.

I suspect that the initial amount of strategy depends on the voters -
that some voters are more inclined to strategize than others. Probably
voters who are used to FPTP would be more strategically inclined,
although I don't have any proof of this (it just seems intuitive). But
Debian used Schulze however many years without having any trouble with
burial (that they could detect, at least), and most places that use STV
nowadays don't seem to have much of a problem with vote management even
though it was pretty common in New York and some Canadian elections that
used to use STV.

In the face of this uncertainty, it's reasonable to want to have a
method that resists strategy well so that it doesn't get repealed after
a disastrous result. But that doesn't mean that it's strictly necessary
- only that we can't tell if it is, and we only get one shot.


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