[EM] reply to venzke - range "random skewing" effect is not a problem

[Juho]

On Mar 13, 2007, at 3:51 , Warren Smith wrote:

> http://rangevoting.org/StratHonMix.html


>> Venzke: These simulations purport to show that Range does  
>> relatively well by SU
> when voters are a mixture of strategic and sincere. This is pretty
> tangential to what I wrote.
>
> --what Venzke wrote was:
>>> Venzke: If I don't want to assume that voters will courteously
>> vote sincerely (even when this limits their power to affect the  
>> results),
>> then I wouldn't use Range, as the result will be rather randomly  
>> skewed
>> based on who chose to exaggerate and who didn't.
>
> --My simulations addressed exactly this. They were not  
> "tangential."   They were
> "a study designed to examine exactly this question." The plan was  
> to set up a situation
> with maximal "random skewing" due to some voters (50%)  
> "exaggerating" and some (50%) "not,"
> and choosing who was who "randomly" by coin toss, and having a  
> small total # of voters
> (61 and 13 voters in the two tables) exactly to make sure there was  
> a large typical
> variation in the numbers of honest & strategic voters in each  
> political camp.
> EXACTLY the situation Venzke was worried about.

Kevin Venzke's words maybe left space for interpreting them to  
include also a situation where each voter would toss a coin to decide  
whether to vote strategically or not. I think the interesting  
scenarios are elsewhere. My understanding is that he had something  
quite different in his mind.

I guess you, as a Range expert, pretty well know what the anticipated  
problematic scenarios are. Problems may arise e.g. when opinion polls  
tell that Democrats would get only 49% of the votes (against 51% of  
the Republicans) and therefore their supporters decide to put some  
additional weight in their votes and vote strategically in Approval  
style. This would make the Democrats win.

It is possible that Republicans would counter by applying the same  
strategy and the situation gets balanced again. But as a result of  
this race on "whose voters are more strategic" Range elections may  
become in essence Approval elections. The achieved results of  
Approval voting are not very bad in terms of achieved social utility.  
The worst scenarios are ones where some parties/groupings vote in  
Approval style while others do not. In these cases it seems obvious  
that the social utility would not be good.

The essential improvement in the simulations would thus be not to  
toss a coin in the same way for each voter (I believe that is what  
you did) but to study situations where voter groupings with different  
opinions have different percentage of strategic voters (maybe having  
"different coins with different strategic and non-strategic voting  
probabilities").

Those different percentages may be a result of seeing different poll  
results and/or getting different advice from the "parties" on how to  
vote. (It is possible that in real life the voting behaviour of  
different groupings would gradually become similar, having roughly  
the same percentage of strategic voters. In this case the  
"equilibrium of recommended voting styles" is however likely to be  
close to Approval style voting in elections that are competitive by  
nature, i.e. when voters are happy to vote strategically to make  
their own alternative win.)

One could thus use the Range method in different ways: 1) use it in  
non-competitive elections, 2) allow strategic/exaggerating/"sincerely  
strong opinion" voters to have more say and make their favourite win  
with improved likelihood, 3) accept the elections to turn into  
Approval like elections as a result of widespread Approval style voting.

Juho




		
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