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First (little bit) of Partisan Data in Daves Redistricting

by: dgb

Mon Nov 30, 2009 at 3:18 PM EST


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

dgb :: First (little bit) of Partisan Data in Daves Redistricting
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.

Enjoy!

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Nice!
I'll have to wait until I get home to try it out, though, but I'm sure it'll be fun.

I'm working a set of shapes for CA and WI
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.

Excellent
Thanks Dave!  

Does this work on existing VTD maps for MD?
If so, where would I see it?

[ Parent ]
Uh oh, it looks like there's a tooltips regression on Mac. . .


[ Parent ]
What's the symptom?
The tooltip on a vtd should show the partisan breakdown on the second line.

[ Parent ]
Two things
1) as in several versions ago, the tooltips often just don't show up (or you have to go back and forth several times to make them show up; and

2) I see no second line, either in the tooltips on in the demographic bar at the bottom of the screen (for the selected district).


[ Parent ]
Tooltips
(1) is a feature. The problem is that populated the thousands of tooltips is real slow (in the Silverlight code), so I populate them lazily.

(2) Not sure. Did you get the dialog box informing you of the number of vtds in the partisan data that did not get matched? When I first posted this diary that didn't work, but someone found it and I fixed it pretty quickly (when diary was updated).


[ Parent ]
As to 1, I understand why you're doing it that way
but it can be pretty tedious to draw a map when it's difficult to get the data to show up.

As to 2, nope, no box. Is there a cache I should clear?  


[ Parent ]
But returning to 1, it would be really helpful
to selectively shade the districts by demographic and political info.  

[ Parent ]
Thank you
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  

for more election analysis, visit  http://frogandturtle.blogspot....




17, CA-06,  


New York
next weekend....

Then it will depend on the help that the community can provide. I'll post another diary describing how that might work.


[ Parent ]
I'm not seeing any partisan data.
Where is it supposed to be?  Am I just not looking in the right place?

Follow the elections in Georgia at the 2010 Georgia Race Tracker.

It's in the same places as racial data


28, Unenrolled, MA-08

[ Parent ]
Ok, that's strange
It's working for me in Firefox by not Safari.

[ Parent ]
Yep not working for me in chrome
but works in Firefox. The pop-up indicating that there is partisan data does not show in chrome, but does in firefox.  

[ Parent ]
LOL. NOT working for me in FireFox but works in IE.


Follow the elections in Georgia at the 2010 Georgia Race Tracker.

[ Parent ]
Weird
On Windows Vista it's working in Firefox and IE for me. Hard to know why. Perhaps multi-line tooltips?

[ Parent ]
Oh man
I'm gonna have fun with this

Some Dude, 19, Democrat, NH-02 (residence), MA-08 (college)

great feature ...
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: http://www.baltimorecity.gov/g...

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.  


This is where I need help
Great comments. This is exactly where I need help. If you (and others like you across the country) can provide solutions to these problems, I can get the solutions into the application to correct this.

For the problem you point out, possible approaches could be:
-- mapping the new districts back into the old;
-- finding new shapes that match the new districts and then
     -- mapping the 2000 population data into those new districts OR
     -- finding population data that matches the new districts

If you have any ideas for Maryland, please let me know.

Thanks!


[ Parent ]
Address List
The MD Board of Elections has a list of precinct voting addresses and another one with reams of data on every election in '08 (with a similar one for '06) that you could use to line things up in almost all cases.

Of course that would be really tedious since there are a lot of precincts in Baltimore City.

I looked at that huge Excel sheet one day for the hell of it after the '08 elections. There were actually handful of precincts in the city where McCain bested Obama, as well as a handful where there were either zero votes or a single vote for McCain. (My own precinct in a mostly white part of town went for Obama by about 3:1.)    

36, M, Democrat, MD-03


[ Parent ]
Suggestion for the App
Allow it to show county boundaries but not county names.

26, male, Dem, NJ-12

Good Idea
And if the CDs are shaped weirdly, the placement of the CD label is not that good.

Thanks.


[ Parent ]
I can give you a hand with Michigan
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.

16, Male, MI-01

More info on how to help soon
I need to move some files around and write up an explanation to make it clear what's needed. Thanks.

[ Parent ]

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