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ancus

Proportional representation

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ancus

Anyone else have a special interest in proportional representation?  Only part of the US currently using PR is Cambridge MA which uses single transferable vote to elect its 9-seat city council and 6-seat school board at-large.  I'm trying to get people in Knoxville interested in it but it is slow going, especially with "rank choice" advocates deliberately trying to get people confused about STV versus instant runoffs.  We also have a provision in state law that limits the number of seats in county commission districts to 3 (not very proportional) and even requires counties with the population of Knox county to separately designate every seat in a multi-seat district (not proportional at all!).  So as a consequence I've been looking into mixed member proportional as well, and developed a version where you can still transfer your vote for candidate and for party. 

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ancus

I'm also very excited about this revision to traditional STV counting methods provided by Kevin Baas https://blog.opavote.com/2016/06/guest-post-rethinking-stv-fundamentals.html

It's very technical but what it boils down to:

Traditionally, STV uses the "Droop" quota, which is the number of vote divided by one more than the number of seats; this is to prevent the majority party from only getting to choose a minority of seats (Baas explains how this happens).  Basically, too many candidates get eliminated too early, so the "Hare" quota (votes over seats) is too high to work.  With the lower quota, the majority party meets quota first and transfers votes to its other candidates and still gets to choose a majority of seats. 

According to Baas, the problem that this is meant to solve is caused by permanently removing eliminated candidates.  If you reintroduce eliminated candidates, then candidates for the majority party stay eligible for longer and are still able to win a number of seats that matches their proportion of the electorate.  You also don't get the degree of over-representation for the majority that Droop causes.  It also reduces issues with "monotonicity": basically, there are special circumstances where a candidate being ranked higher on the ballot makes them less likely to win (it is non-monotonous) which in my opinion is actually one of the best arguments against STV.  Well, the Baas system reduces or eliminates non-monotonicity, because much of it is caused by the same problem of permanently removing eliminated candidates.  You also get rid of the problem where a party can nominate too many candidates and they will be "split" in terms of first choice rankings and also get eliminated too early (basically, any problem resulting from candidates getting eliminated too early is removed by reintroducing them). 

He also does something called "full elimination ordering," which according to the comments appears to take a titanic amount of time.  This is the part that completely removed non-monotonicity, although simply reintroducing candidates still reduces it quite a bit, just not down to zero.  I think it takes too long to be worth it.  Each candidate is placed in order of how many "rank demotions" would be caused if they were taken out of the count.  One rank demotion is where a candidate on one ballot is removed, so that ballot counts for its second choice instead of its first.  Two rank demotions is when it counts for its third choice instead of its first, etc.  This would be impossible to do by hand, but the reintroduction and the higher quota should take only a little more time than traditional counting methods. 

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ancus

I did not define single transferable vote.  There's a lot of explanations out there, but they all boil down to this: candidate-based proportional representation.  Instead of matching a number of seats to a party, based on the number of votes for that party (mixed member proportional and lists systems), a seat is matched to a number of votes, and a candidate with that number of votes is elected.  That's where the transfers come in. 

Since you can't make the right number of people vote for each candidate, you allow them to rank as many candidates as they want in the order they want (Australia has a slightly different system, where you have to rank a minimum number of candidates, but you can get out of it by using a ranking provided by a political party).  Ballots are counted in rounds and each ballot counts exclusively for the first choice, until 1)the first choice candidate is elected, in which case excess votes for that candidate are divided among second choices, or 2) in a round where no candidate is elected, a candidate has to be removed from the count, and the ballots recounted until another candidate meets quota.  The process continues until all seats are filled or there are only as many candidates as seats. 

For a more visual example: imagine a gymnasium with a certain number of squares, enclosing chairs for "voters" to sit in.  Each square is a candidate.  When a square fills up, the candidate wins, and any more prospective supporters would look for a different but similar square.  If everyone is sitting down and you still need to choose more winners, you remove the square where the fewest people are sitting, and those people will look for new spots.  Assuming none of your voters get "exhausted" (or run out of choices they support) eventually each square will have an equal number of voters and each voter will have a real representative. 

In real life of course you will lose some people--the fewer seats you elect, the more people you lose.  Doing it on paper, with rankings, is easier, more accurate, and protects your voters' anonymity.  But hopefully you should get the basic idea. 

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