[EM] More on Gerrymander prevention

Jurij Toplak jure.toplak at uni-mb.si
Wed Mar 20 10:00:55 PST 2002

What you are refering at is called "automated redistricting process" -
getting the districting plan by following certain mathematical formula and
not involving in the process any human bias.
There has been quite some literature written on such procedures. I have
written a master thesis on the topic "Protection of equal voting right by
redistricting process rules". I wrote about automated redistricting. It has
not been published anywhere, but if anybody is interested, I can send it to
you by email.
You can also check Micah Altman's Harvard Ph.D. thesis "Districting
Principles and Democratic Representation" and its 5th chapter "Is Automation
the Answer? -- The Computational Complexity of Automated Redistricting". It
is at http://data.fas.harvard.edu/micah_altman/disab.shtml

Altman is saying that automated redistricitng is not practical and possible,
but I am saying that it is possible and I also developed a method and used
it on a practical example - my country.

----- Original Message -----
From: Michael Rouse <mrouse at cdsnet.net>
To: <election-methods-list at eskimo.com>
Sent: Wednesday, March 20, 2002 6:28 PM
Subject: [EM] More on Gerrymander prevention

> Note: this is more of a thought experiment than a serious suggestion --
> number of states and districts is not a power of two for one thing, and
> there are problems with long, skinny districts -- but it does show an
> automated way of coming up with a single apportionment answer, and it
> point to a method we can agree on.
> To illustrate, assume we want to break up the United States into 64
> or perhaps Canada and Mexico have combined with the United States to form
> North Americal Union and we want to divide the Union into 64 regions. Find
> the population centroid for the country, then find the geographic
> Draw the great circle that runs between them and continue until the line
> reaches both borders. You now how two clearly defined sections of roughly
> equal population. Find the population and geographic centroids for each of
> these sections, draw another great circle line for each set, and continue
> until you have 64 states (regions). Each "state" should have *roughly*
> area and population. (I say "roughly" because of the teeter-totter
effect --
> a small group of people far away will balance a larger group nearby --
> is why I have it going through the geographic centroid as well.) As an
> alternative, you could use the point where the north-south population
> crosses the east-west population median, then take the line between that
> the geographic centroid. In either case, everyone who followed the
> definition accurately would end up with the same result, regardless of
> party.
> Instead of a power of two, we could redo the lower 48 contiguous states.
> Ignoring Alask and Hawaii, cut the country in thirds -- Pacific, Atlantic,
> and Central -- with equal populations, and the borders defined by
> lines (in other words, find the line of longitude where one third of the
> population of the country is west of the line, and then find another where
> one third of the population is east of the line. Those two lines will
> the country cleanly). Within these three regions, find the population and
> geographic centroids, draw lines through them, and repeat until each
> has 16 "states," giving a total of 48 states. We can keep going within
> states until each state has 8 districts, or 384 districts plus Alaska and
> Hawaii, as opposed to 435 districts we have now. (We could of course do
> same thing with lines of latitude -- north, middle, and south -- and
> each region into 16 parts, but lines of latitude are not great circles,
> the regions would be more elongated to begin with).
> As mentioned above, one of the problems is that you could easily end up
> long, skinny, not-at-all-compact districts. Another problem is the
> would completely ignore present political, historical, racial, and
> geographic groupings -- it might take a thin sliver out of the center of a
> city but extend far out into rural areas, and across our present state
> boundries. On the other hand, each district would be a simple, closed, and
> convex figure, with a near-minimum of jaggedness, and there would be only
> one result possible for each census. The tesselations would also make a
> mosaic (grin).
> If the results were too strange -- districts stretching acrossed time
> or shaped like slivers of glass -- the population centroid of each
> could be used as a "seed" result, with an algorithm moving census blocks
> between districts to make each each district more compact. This would
> some variability, but the "seeds" would limit the amount of gerrymandering
> possible.
> Michael Rouse
> mrouse at cdsnet.net

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