[EM] polls and manipulation

[Jonathan Lundell]

On Nov 21, 2008, at 11:00 PM, Juho Laatu wrote:

> Here's one IRV example with three strong candidates and where voters  
> do have some incentive to compromise.
>
> 45: A>B>C
> 10: B>A>C
> 15: B>C>A
> 30: C>B>A
>
> We have one centrist candidate (B) between two others.
>
> According to this poll it seems that B will be eliminated first, and  
> then A would win since some B supporters prefer A to C.

And where is this poll coming from? Even in an election that's polled  
obsessively, with only two viable candidates, the poll results are all  
over the map: http://www.pollster.com/blogs/pollster_accuracy_and_the_nati.php

We see popular-vote polling predicting Obama's margin as anything from  
+2 to +11.

Vincent Conitzer and others have been doing some interesting work on  
how easy/difficult it is to manipulate an election by changing votes.  
An interesting corollary question is: how much information does a  
manipulator need about the election profile in order to have a decent  
chance of success?

One can imagine circumstances in which manipulation is easy (for Nader  
supporters in Florida 2000, say), but, intuitive or not, how is a  
voter going to have the kind of information (and confidence in it) to  
successfully manipulate the above example. Not to mention the  
recursive tangle we get into if we assume that *all* the voters share  
this information...