[EM] Student government - what voting system to recommend?

[Juho]

On Apr 23, 2007, at 22:34 , Abd ul-Rahman Lomax wrote:

> At 02:14 PM 4/23/2007, Juho wrote:
>> Let's say that in the U.S. presidential elections roughly 48% of the
>> voters vote D=9, R=7, PW=1 and roughly 48% vote R=9, D=7, PW=1.
>> Either D or R wins.
>
> The premise is utterly insane and, quite simply, not reasonable.  
> Range is difficult to analyze through the simplistic "this block  
> voted this way" kind of analysis we are accustomed to using for  
> election methods.

Ok, this example was not intended to describe a real life situation  
but just to demonstrate theoretically how a Range based system might  
change in time.

> In the real world, there is a set of voters who are dedicated party  
> supporters, and then there are other voters, perhaps the majority,  
> who aren't so nailed to a party. A minority, perhaps, would vote as  
> described. And, in fact, they are much more likely, I'd suggest, to  
> rate a third party candidate higher.

Another explanation to the emergence of Approval style strategic  
voting is that an individual voter might learn that, in a case where  
there are only two candidates that have chances of winning the  
election, voting A=9, B=0 instead of A=5, B=4 makes his/her vote 9  
times stronger. Similarly he/she could learn (maybe from experts)  
that in general voting in Approval style (as defined in the well  
known Approval strategies) in elections where there are several  
potential winners typically gives him/her the strongest voting power.

I used this style of explanation since this explanation does not talk  
about parties, or voters belonging to them, or about the candidate  
set-up, but only about the strength of the vote of the individual voter.

> Further, note that the PW candidate now gets zero from this group.  
> That's really not much different from the vote before. But it is  
> totally unnecessary. Why would these voters suddenly drop their  
> (small) support for the candidate with no chance to win?

Rating the least preferred candidate at 0 reduces the probability of  
that candidate getting elected (and doesn't carry any risks with it).

> If you are going to propose that Range will *reduce* to Approval,  
> you will have to use reasonably likely scenarios.

I think the vote strength argument that I presented above is quite  
generic and applies in all typical elections - assuming that we talk  
about competitive elections where the voter wants to do his/her best  
to make his/her favourite alternative win.

> The fact is that if even the majority of voters bullet-vote, it has  
> not reduced to Approval.

I expected the voters to vote in Approval style (not to bullet-vote,  
although in this particular example the best Approval strategy for  
the mentioned voters was to bullet-vote).

> spoiler effect

(Approval and Range are less vulnerable to the spoiler effect than  
plurality.)

> And if it *does*, under some difficult-to-anticipate circumstance,  
> reduce to Approval, that isn't a bad outcome!

Approval is not very bad. There are different ways of describing  
Range to the voters. I think a description that advices voters to  
indicate their sincere utility values of the candidates in the ballot  
is not a good description since that makes those voters that vote  
strategically (Approval style) and not as told more powerful than  
those that vote as told. Defining Range as "like Approval but with  
option to give only weaker fractional preferences" would be more fair.

> I have also suggested that if the analysis of Range ballots shows  
> divergence between the Range winner and a Condorcet winner, a  
> runoff be held between the two. Some, seeing this, imagine that the  
> outcome of the runoff would be that the Condorcet winner would  
> prevail. If true, that's fine with me. However, it is much more  
> likely to occur that the voting public would take into account how  
> everyone else voted, and *might* vote to, instead, elect the Range  
> winner. After all, that is the winner who, the poll indicated,  
> would maximize voter satisfaction. How important is that to *you*?

Let's assume that a Condorcet winner exists. In this case this method  
could be said to be a method where the voters are given a second  
chance to think again if the Range winner could be seen as a "good  
compromise" even though the majority could easily vote as in the  
first round and elect the Condorcet winner. I'm not sure this method  
would be a very practical method in real life large elections but in  
principle the idea of "recommending" the Range winner to the voters  
is a positive idea. Some strategies where people would try to  
influence who the Range winner will be could take place (i.e. the  
Range winner of the second round would not be the sincere range winner).

Juho



		
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