
Show HN: Antimander – Optimize Congressional Districts with Genetic Algorithms - joelS
https://antimander.org/
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splitrocket
"I cut, you choose" is really the only politically viable alternative to the
current state of affairs.

[https://slate.com/news-and-politics/2018/02/how-the-i-cut-
yo...](https://slate.com/news-and-politics/2018/02/how-the-i-cut-you-choose-
method-of-redistricting-could-fix-a-broken-system.html)

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chrisbrandow
It would require a more fundamental recognition of political parties than the
constitution provides.

Gerrymandering is not a technological problem.

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fastball
Why can't you just split elected representatives into two groups, regardless
of stated political affiliation? One group then cuts, the other chooses.

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specialist
Defections. Electeds will happily maximize their own personal power at someone
else's expense. There are many examples of getting opposition support for
inequity in exchange for safe seats.

People outside of (partisan) politics don't often get to see that the party
orgs and the politicians are usually in conflict. More so on the left than on
the right.

~~~
splitrocket
Interestingly enough, this works even for defectors. They still have to
participate in a turn-based game against a competitor.

There is a whole field of study around efficient "cake cutting" algorithms,
many of which contemplate and account for defectors.

[https://en.wikipedia.org/wiki/Fair_cake-
cutting](https://en.wikipedia.org/wiki/Fair_cake-cutting)

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jojobas
>Some interesting patterns emerge, such as how with you can have compact and
republican-biased but not compact and democrat-biased maps for some numbers of
cities. This is a direct result of one party being forced into a small
geographic area (cities).

That's quite an interesting finding. I always understood that gerrymandeting
is bad because the artificially winning parties get congressmen that are not
representative of their districts. This guy uses "competitiveness" as a
property worth optimizing for, achieving exactly that.

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specialist
I've long advocated maximal competitiveness. Mostly to motivate voter
participation.

I love how antimander illuminates the tradeoffs.

Along the lines of "preserving community", preserving continuity can also be a
factor. On the presumption that voters don't want to have their congressional
district designation changed every 10 years. For example. I know this is a
consideration during redistricting.

\--

Antimander is real progress. The cites are terrific. I'm delighted that I even
learned some new things, like the Seats-Votes Curve.

I've spoken with the Dave Bradlee many times over the last 15 years. He
created a redistricting app that got some national media attention last cycle.
[https://en.wikipedia.org/wiki/Dave%27s_Redistricting](https://en.wikipedia.org/wiki/Dave%27s_Redistricting)

Some of those talks were pretty bleak. I'm so glad so many more people have
engaged with this issue.

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c54
This is really well done! Do you have analysis of what this would do
nationwide or across multiple states? Optimizing for competitiveness is a
metric I hadn’t considered but seems particularly valuable especially towards
increasing voter turnout.

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jojobas
How is it valuable? Having a "red" or "blue" district means the congressman is
somebody most people can get behind, "our guy in the parliament".

Being around 50% gives you a compromise that nobody trusts and nobody feels
the stake in their country.

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rpedela
On Android and Chrome, I can't read the page. The graphic takes up half the
screen and the text underneath is barely visible.

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pdxandi
I had to scroll all the way to the bottom to see if anyone could even read the
site on mobile.

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gillesjacobs
Gerrymandering is a danger to democracy and it is great that researchers shine
light on the different trade-offs of districting criteria.

This website seems like a great demonstration of the fairness and
competitiveness trade-offs.

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usrusr
I'd argue that every voting system that has gerrymandering as a possibly error
mode is inherently dangerous. No amount of antimandering could ever be more
than a temporal band-aid. There are many examples that successfully combine
local representation with proportional outcome.

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steve_gh
Interesting. GA's have some interesting use cases. We used a GA to optimize
assignment of work crews to areas as part of a scheduling optimization, and
achieved significant benefits

Steve

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kwaldman
Seen similar benefits - many years ago applied GA's to schedule technicians to
fix computers (based on location, part availability, skill set, etc) and also
for manufacturing production lines (labor rules, parts, color changeovers,
demand, margin)

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IgorPartola
As Congressional elections become more and more a national affair, why do we
still have districts? Say a state gets 24 reps. Give me a ballot with all the
candidates and let me mark the 24 I want. Yes the ballot will be more
complicated, but this way we entirely avoid districting and the process is
entirely fair (well until you consider states not being fairly drawn, but
that’s one level up).

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coldcode
Likely it means that big cities would get all the reps and the rest of the
state gets nothing.

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jgeada
As that is where most of the people live, why is it wrong? Why does largely
unpopulated land get a vote?

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IgorPartola
This. Why do voters living in rural areas get more weight to their votes? This
is obviously more pronounced in the Senate, but clearly also a problem in the
House.

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charleskinbote
Along the same thread, genetic algorithms have been used to evaluate fair land
allocation in Brazil [1], which have also historically been done by hand. I
agree with another user that pointed out the very same tools can be used to
gerrymander even more effectively than those districts are currently, perhaps
in less obvious ways, without the oddly shaped borders that stretch wildy from
place to place. It would be important not to have this occur behind closed
doors but left open to scrutiny where the fitness function and biases are in
full view.

[1]
[https://www.lume.ufrgs.br/bitstream/handle/10183/174950/0010...](https://www.lume.ufrgs.br/bitstream/handle/10183/174950/001065460.pdf?sequence=1)

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xorfish
How hard would it be to change the congressional election system to
proportional voting by party?

In California you would vote for 53 representatives, each representative would
be part of a party. First the seats are divided among all parties based on
some system. Then within each party the seats are given to the representatives
that have the most votes within the party.

This would introduce new parties to the system, no party would be able to
govern alone.

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cbuq
Would this require me to make 53 different votes? This sounds a like pretty
complicated situation to expect educated votes for all 53 votes.

~~~
rsynnott
In practice, in mostly countries that use STV PR, you have smaller electoral
districts, for this reason. For instance, in Ireland, electoral districts
elect 3-5 TDs depending on population. This is big enough to make
gerrymandering difficult and not very effective, but small enough to avoid the
situation where someone has to cast 53 different votes. And 53 would be the
low end here, really. That would assume you only want to vote for one
candidate per seat, which is not typically the way it works out. I'm in a four
seat constituency and voted about ten preferences in the last election, say.

In practice, in STV PR it is generally optimal to vote for almost everyone on
the ballot; you give low preferences to people you don't care about to avoid
people you actively don't want getting in (it's commonly claimed that you
should optimally give a preference to everyone, even those you actively don't
want, but this is incorrect).

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nicolaskruchten
I've always like this article's thoughtful approach to what we should value
when districting: [https://www.politico.com/magazine/story/2015/06/could-
gerrym...](https://www.politico.com/magazine/story/2015/06/could-
gerrymandering-be-good-for-democracy-119581)

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FiReaNG3L
Interesting to note that the very same tool can be used to optimize the
'worst' maps as well.

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bargle0
Now do Maryland.

