Category Archives: shortest_splitline article – Redistricting: Should Computers Draw the Lines?

Josh Goodman has an interesting article up about redistricting algorithmically (An idea which I support):

Redistricting: Should Computers Draw the Lines?

What’s more, the maps only would be as good as the formula that Tim or Mike Fortner or anyone else wrote. Fortner pointed out that some elements of redistricting are awfully difficult to code. How do you tell a computer to abide by the Voting Rights Act, which is a matter of judicial interpretation?

Fortner did say that a computer might be able to handle a relatively simple map, like Iowa’s congressional districts. Iowa is overwhelmingly white, so it doesn’t have to worry about Voting Rights Acts compliance in redistricting. It only has five congressional seats. And it has a rule that counties can’t be divided. Of course, the same factors that make it an easier place for a computer to draw a map also make it an easier place for humans to draw maps. “The computer is best as a tool to guide people,” Fortner told me, “and let them know how they’re doing.”

Just to make sure my idea was bad, I posed it to a couple of panelists discussing technology in redistricting at the National Conference of State Legislature’s annual meeting in Louisville (where I am this week). Kim Brace, president of Election Data Services Inc., said there actually has been quite a lot of academic research into using computers to redraw maps — with lousy results. “If you think legislative plans look crazy,” he said, “wait until you see what a computer does.”

Mark Stratton, who works on redistricting with Indiana’s Legislative Services Agency, made another point: A redistricting plan only does any good if legislators are willing to vote it into law. “The computer,” he said, “can’t vote for the plan.”

At first, that comment struck me as missing the point. Whether the maps are drawn by humans or computers, there are plenty of ways to structure the redistricting process so that lawmakers have no choice but to accept proposals that abide by objective criteria. Fortner’s constitutional amendment would have done just that in Illinois.

But, the more I think about it, Stratton was making the critical point. People are perfectly capable of drawing fair, reasonable congressional and legislative lines. When states end up with unfair, unreasonable lines, it isn’t because no one could figure out how to draw a better map. The reason is politics.

The Rose Report on algorithmic redistricting

The Rose Report discusses algorithmic approaches to redistricting such as the shortest-splitline algorithm.

The Rose report points out that these algorithms could be unconstitutional and seems to consider algorithmic redistricting approaches to be politically naive.

A recent letter-to-the-editor in The Appeal-Democrat suggested we just draw district lines according to latitude across the state to create the areas our legislators represent. Many people say such things, not unreasonably, because they are ignorant of the fact that such districts would inevitably be unconstitutional.

The idea behind such proposals is simple: people want to take the “politics” out of redistricting politics in a complete and total manner. Of course, in practice, trying to take the politics out of politics is as nonsensical and impossible as the verbal formulation. Further, such reforms might cause more problems than they would ever solve. Such exercises can be valuable as thought experiments, but realistic reforms strive for something much more moderate and, for lack of a better word, political.

I disagree with the assertions made by the Rose report that algorithmic approaches to redistricting are forever unrealistic reforms.

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CA voting rights act only applies to at-large voting systems

(Yes, yes, I know that I still need to research the federal voting rights act and it’s impact on gerrymandering. Now I’ll also need to be aware of it’s impact on proportional representation systems.)

California has a voting rights act enacted in 2002. You can read about it at fairvote and at National Demographics Corporation (NDC) Research (and here is a pdf: NDC Research).

The act can cause local governments that use at-large methods of elections (as opposed to single-winner districts) and that have under-representation of minorities to have court enforced remedies imposed on them. The act implies that those remedies are typically the imposition of a single-winner districting solution.

The city of Modesto was sued in 2004 under this act and lost. They have a 25% Hispanic population but since 1911 one Hispanic city council-member has been elected for their at-large 5 member council. The city is counter suing and argues that the California Voting Rights Act violates the U.S. Constitution. It will be interesting to see how this develops.

The CA voting rights act seems to have a bias that at-large elections are the only source of distorted representation and that single winner districts is the preferred remedy. These assumptions should be questioned.

shortest splitline algorithm vs voting rights act?

When we first discussed the shortest-splitline algorithm for eliminating gerrymandering, Warren D. Smith had commented on the potential issue that current law mandates majority-minority districts.

The “issue” that gerrymandering to make majority-minority districts is required by law… sounds interesting. I encourage you to actually look at the law and inform us what the heck you are talking about.

Alas, I never did do that research. I had originally suspected that this might be so from the redistricting game.

It looks like Warren has now heard the same message from CA Secretary of State Debra Bowen while attending the Electronic Voting technology Workshop in Boston.

Here is what Warren has said on the matter:

CA secretary of state and heroine D. Bowen was there listening to the talks. I sat next to her at lunch and tried my best to give her the goods. But she’s very knowledgeable. I’m impressed. She said shortest splitline would be illegal under the voting rights act. Basically her argument was that gerrymandering is mandated by the VRA to create “majority minority” districts and splitline would prevent that hence is illegal, QED.

I suppose that I (or someone) should do the legwork to read the voting rights act to see what it has to say on the matter.

pics of CA gerrymandering and how the splitline algorithm would do it

Nick requested to see CA districting under the shortest splitline algorithm.


In 2004, not one of CA’s 173 state legislative and federal congressional seats changed party-hands. In 2002, every incumbent won re-election, on average with 69% of the vote. California may be the new gerrymandering champion, perhaps even worse than Illinois and Texas, but unlike them its gerrymandering is “bipartisan” that is, arranged by agreement among the Democrats and Republicans to “design their own districts” to make every office holder “safe.”

CA districts under the shortest splitline algorithm:
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some proposed reforms to the problems of gerrymandering

If one insists on electing members of a legislative body via districted single-winner elections then the problem of gerrymandering will surface.

Can gerrymandering be solved?
There are a number of proposed reforms out there. Continue reading