First (little bit) of Partisan Data in Daves Redistricting

Last night I uploaded upgraded software that can handle partisan data. The state of Maryland is the first state (and only so far) to include that data. There are some caveats (below the fold). Also, keep checking here for ways you can help get more partisan data.

[Update: there was little glitch so partisan didn’t show up, but it should work now! Thanks!]

Daves Redistricting App

One other thing that’s new: all states where the Census Bureau has voting district shapes from 2000, except New York, now have voting districts (in addition to block groups for many) enabled in the application. (New York will be added soon with new voting districts [thanks Jeff!])

The big caveat:

The voting districts shapes and population data come from the 2000 census. Many states changed their voting districts between 2000 and 2008, so the 2008 presidential data does not match completely. For Maryland, for example, over 200 new voting districts were created during that time, so only 1600 of 1800 match the 2000 districts. The application lets you know when this happens and then simply ignores the new districts. This could be improved if someone is able to merge the new districts data back into the old districts.

I will be asking for help to pull together partisan data for the other states. Mostly this will involve putting the data into a particular form, where the districts are identified in a way that matching the district shapes. Keep checking here (next weekend) for information on that.

A few states, important ones for redistricting, did not give the Census Bureau voting district shapes. Those states are AZ, CA, FL, OH, OR and WI. The app still supports only block groups for those. How to get partisan data for those is a good question. it could be that someone can map voting district data into block groups, or produce voting district shapes. Ideas are welcome.


26 thoughts on “First (little bit) of Partisan Data in Daves Redistricting”

  1. The statewide database at Cal has some good info, but it just needs to be refined a bit further and pieced together with population data.

  2. Thanks alot for getting the data onto the App in Maryland. Do you have a rough estimate of when you will have partisan data for other states? Thanks  

  3. but please note that, at least for Maryland, the trickiest part to update/correlate will be Baltimore City.  Not only were precincts added there over the last 8 years, but many (perhaps even most ?) of the precincts have been renumbered.  So the data that shows up currently on the application may be way off —

    for ex., part of Cherry Hill in south Balto. (which is a neighborhood that is almost all African-American) is showing up as 49 Obama/45 McCain.  The reason is that it’s listed as precinct 25-11.  The “real” (current) precinct 25-11 is just accross the Patapsco River in the Brooklyn part of the city (which is labeled 25-12 on the application)… you can see on this map of current precincts:

    Balto. City is by far the worst in terms of this.  (The other area I remember from when I did diaries for Maryland a few months ago is that parts of northern Prince George’s County were also like this).  Much of the rest of the state, you only have to deal with the additional 200 or so precincts that have been added, as the precinct numbers tend to “stay in place” geographically, but in Balto. City it may be particularly cumbersome b/c of the annoying renumbering.  

  4. There really isn’t much point including partisan data for Michigan because I know that all of the precincts in Detroit have been completely renumbered, but I do have a map of the 2008 Precincts for Detroit, Grand Rapids, Pontiac, Flint, Marquette County, and I’m sure I could find others.

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