[EM] IRV proponents figure out how to make IRV precinct-summable

[Brian Olson]

On Mar 22, 2009, at 4:24 PM, Kristofer Munsterhjelm wrote:

>> Again, the election method better get decided on before the  
>> election, so that the voters can be told the rules and thus be able  
>> to express their thoughts to whatever extent they choose within  
>> what those rules support:
>>     Condorcet:  A=B is fine for about equals; A>B or A<B ranking  
>> for different liking, but amount of difference is neither needed  
>> nor expressible.
>>     IRV:  like above, except A=B not permitted, for counting would  
>> not know what to do when A=B must be deciphered as top ranks.
>>     score:  ratings must be decided - for A>B>C, obvious to rate A  
>> high and C low, but where to place B to get maximum or minimum  
>> difference between A and B or between B and C is difficult.
>
> I'm not sure about IRV - has anyone devised an STV variant that  
> handles equal rank? If not, then you're right - again, I'm not sure.
>
> From what I've seen of voting equipment, most limitations seem to be  
> in the name of expediency. For instance, SF's RCV three-rank method  
> keeps voters from ranking more than three candidates - probably to  
> accomodate existing equipment.
>
> What limitations may exist (such as your IRV example) may be handled  
> by having a voting machine that permits all ranking types (full,  
> truncated, equal rank), then having parameters that limit according  
> to what kind of voting system is being used in the back end (e.g no  
> equal rank).

All of my implementations of election methods in software allow for  
equal rankings. In IRV or STV they cast a 1/N vote for each of N tied- 
rank active choices. (If I were to vote for A and B in some round, I'd  
cast 1/2 vote for each, but if one got eliminated, I would cast a full  
vote for the remaining one in the next round.)
If you like Java, peek at this:
http://code.google.com/p/voteutil/source/browse/trunk/java/org/bolson/vote/IRV.java

I would also like to note to Raph that hosting files on the yahoo  
groups is making them not viewable to me, because I don't feel like  
jumping through yahoo's hoops right now.