[EM] Redistricting Paper w/ New Population Density Fairness

[Kathy Dopp]

Jameson,

After further reflection, I think your claim #1 below is misleading
because if a plan was chosen with population density fairness (PDF)
value of nearly one (1), it would tend to have far fewer "safe"
districts than a plan with PDF value near two which was gerrymandered
to give a disproportionate number of legislative seats to the minority
party.  Also, if a plan with PDF about one (1), thus a proportionately
fair plan, was chosen, it depends on the overall proportion of various
partisans within the state whether or not it would produce fewer or
more "safe" districts than a plan with PDF value near zero where the
majority got all the seats in the legislature.

I.e. I disagree with your claim #1 re. my PDF value, because it only
seems to be true in one case, when judged against plans with PDF
values near zero.

I still have a headache. Your other claims may make perfect sense.
Upon reflecting upon your excellent observation about being able to
use a similar measure to evaluate proportionate fairness for diverse
ethnic groups, yes, that is very true.  Great observation.

FYI, everyone, I've made some quick revisions to respond to Warren's
comments and reposted the paper, which I shall continue to revise as I
have time.

http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1945879

Thanks for your comments, which I shall eventually add in some form to
the paper and credit you in the acknowledgements section.

Kathy

>   3. Re: Redistricting Paper w/ New Population Density Fairness
> From: Jameson Quinn <jameson.quinn at gmail.com>

> I like your PDF a lot. You could also use the same idea to measure
> minority/majority fairness for a given ethnicity (but probably not more than
> one, without getting into the problem of optimizing on too many dimensions).
> The problems I see:
>
> 1. If the measure being equalized (population density or minority status)
> was too highly correlated with partisan status, it would tend make too many
> uncompetitive "safe seats". This could in principle be mitigated by
> statewide rules which reduced the advantage of incumbency in the party
> primaries... but I don't trust that to happen. Still, safe seats are on the
> whole less of a problem, in my view, than nonproportional gerrymandering; so
> I'd be willing to accept this price.
>
> 2. If the partisan/population density relationship was not linear, a clever
> gerrymander could take advantage of that fact. I doubt this would be
> possible without ruining compactness, though, so again, not too huge a
> problem.
>
> 3. It's not as good as a good proportional representation system. But it's a
> far less radical change which doesn't pretend to be. So this is not really a
> criticism; more just a comment.
>
> Jameson
>

Kathy Dopp
http://electionmathematics.org
Town of Colonie, NY 12304
"One of the best ways to keep any conversation civil is to support the
discussion with true facts."
"Renewable energy is homeland security."

Fundamentals of Verifiable Elections
http://kathydopp.com/wordpress/?p=174

View some of my research on my SSRN Author page:
http://ssrn.com/author=1451051