[EM] Strategy and Bayesian Regret

Tue Nov 1 18:36:22 PDT 2011

Hi Jameson,

--- En date de : Ven 28.10.11, Jameson Quinn <jameson.quinn at gmail.com> a écrit :

De: Jameson Quinn <jameson.quinn at gmail.com>
Objet: Re: [EM] Strategy and Bayesian Regret
À: "Kevin Venzke" <stepjak at yahoo.fr>
Cc: election-methods at electorama.com
Date: Vendredi 28 octobre 2011, 11h44

2011/10/28 Kevin Venzke <stepjak at yahoo.fr>

Hi Jameson,

I am a little short on time, to read this as carefully as I would like, but if you have a
moment to answer in the meantime:

--- En date de : Ven 28.10.11, Jameson Quinn <jameson.quinn at gmail.com> a écrit :

voting is best. But how do you deal with strategy? Figuring out what strategies are sensible is the relatively easy part; whether it's first-order rational strategies (as James Green-Armytage has worked out) or n-order strategies under uncertainty (as Kevin Venzke does) 

3. Try to use some rational or cognitive model of voters to figure out how much strategy real people will use under each method. This is hard work and involves a lot of assumptions, but it's probably the best we can do today.

As you might have guessed, I'm arguing here for method 3. Kevin Venzke has done work in this direction, but his assumptions --- that voters will look for first-order strategies in an environment of highly volatile polling data --- while very useful for making a computable model, are still obviously unrealistic.

[end quotes]

I am very curious if you could elaborate on my assumption that voters will "look for
first-order strategies in an environment of highly volatile polling data." I'm not totally
sure what you mean by first-order vs. n-order strategies, 

First-order strategies are strategies which work assuming all other factions' votes are unchanged. Second-order strategies either respond to, or defend against, first-order strategies. I guess that your system, through iterated polling, deals with "respond to", but it is incapable of "defend against".

Hm, I'm really unsure what the latter distinction is.

It's true that my voters seem unwilling to risk ruining the result as a form of threat
or deterrent to other voters. I suppose this is because my voters don't understand
how other voters might hypothetically choose to operate. But I'm not sure if this
is what you're talking about.

and whether your criticism
of unrealism is based on "voters will look for..." part or on the "highly volatile polling 
data" part.

Some of the former (lack of defense), but mostly the latter. 

Also, it's not so much a criticism, as a pointer for what comes next. You have absolutely gone farther than anyone else I know of in exploring the motivators and consequences of strategy across voting systems, and if my appreciation of that fact didn't come through, I'm sorry. (Green-Armytage has some answers you don't about motivators, and Smith's IEVS has some about consequences, but your work is by far the best for combining the two.)

No need to apologize for anything. I'm open to criticism at least if I can understand 
it. Personally, aside from the above mentioned point, my major criticism of my sims
is that it can't consider nomination strategy. There is no way to show whether a
given set of candidates is a realistic set of nominees for the electorate under that
method.

I don't really understand what you might mean about the motivators and 
consequences. Maybe you say in later posts I haven't read yet.

I wonder if this volatility is a matter of degree or a general question of 
approach.

Well, I've never seen you try to justify the volatility in terms of realism. It's a computational trick, to prevent excessive equilibrium, from what I can tell. That is, your unrealistic (perfectly rational in some ways but utterly lacking in any meta-rationality) voters may need this unrealistic assumption to give more-realistic answers, and if so, then "fixing" this one issue is not the answer. (If there were no volatility, I think that your system would end up comparing a lot of 100%/0% numbers, which doesn't discriminate very well between systems.)

Well, what would be a realisic way to simulate the uncertainty of polling in real 
life? A given poll in reality usually only consults a tiny percentage of the electorate.
Thus you get "statistical ties." So I think it's fairly accurate to simulate this by 
having random percentages of the voting blocs participate in each poll.

Kevin
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20111102/92f04911/attachment-0003.htm>