[EM] Re: Election redistricting

Ernest Prabhakar drernie at mac.com
Thu Jan 8 08:23:02 PST 2004

Hi Matt,

On Jan 7, 2004, at 5:40 PM, matt at tidalwave.net wrote:
> There are algebraic process for obtaining an initial feasible solution 
> for a given integer program model. I don't know if it is possible to 
> use initial conditions to significantly change the probability that 
> the outcome will be favorable or unfavorable to a particular political 
> party or candidate.  But it is easy enough to formalize the process of 
> obtaining an initial feasible solution so that it is well defined and 
> not subject to politically motivated manipulation.

My point about the integer program model is that, while it may 
technically be deterministic, such a deterministic would be highly 
sensitive to algorithm details (e.g., do you start from the top or 
bottom of the state) and tiny population fluctuations.   Minor errors 
in input would lead to drastic changes in output, and anyone who 
disliked the results would find ample excuses for challenging it.

While such randomness issues would almost certainly NOT benefit any 
particular candidate, I think there are other issues involved.    
People like to think that elected representatives represent a region.  
A pure "integer program model" would have no respect for communities, 
drawing boundaries wherever it minimized circumference, even if it 
meant slicing off small parts of a community at random.  District 
boundaries would also tend to change radically when redistricted.

Now, maybe we on this list like the idea of purely random districts 
that change dramatically and unpredictably every ten years.    However, 
the politicians surely wouldn't -- and not only for selfish reasons. it 
makes it harder to build any sort of coherent connection with your 
district, and the communities that make it up.   This in turn would 
make it much harder to sell to the general public.

Therefore, as a -practical- matter, I think any such computation 
redistricting has to be done in a way that reflects "natural" community 
boundaries.  This should lead to:
a) more recognizeable  and defineable districts
b) greater resistance to small fluctuations
c) greater stability across redistricting events

Of course, such initial conditions do have the potential to benefit one 
party over another (say, by enhancing the voting weight of cities).   
Therefore, it would be wise to test this out in simulations before 
giving it to the politicians.  However, I do think computational 
redistricting needs some sort of 'sensibility' check.  Otherwise, you 
might end up with the sort of public outcry we've seen with the 
computerized college Bowl Championship Series.

Put another way: there are no unbiased algorithms, only hidden biases; 
its better to get them out and explicit so that they can be debated and 
decided upon.

> I don't enough about the other optimization methods such as simulated 
> annealing and genetic algorithm to comment on them.  I don't care what 
> method is used.

Fair enough.  The principle is the main thing.  If we could agree on 
that, implementation is a detail.

-- Ernie P.

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