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by Michael Nielsen on November 7, 2004

Second update and warning: Apparently there was a bug in the analysis described below. Please disregard, and look instead at my later post.

Michael Gastner, Cosma Shalizi, and Mark Newman have developed some astonishing maps of the US election results. There really are two Americas, but it’s not the two people talk about. Rather, US Counties divide up into two sets:

1. Counties (about 400, for a total of 6 million people) where essentially everyone votes Democrat.

2. The remaining Counties, which follow a more or less typical Bell curve, with the mean County about 60% Republican, and 40% Demcrat.

Their results are so stark that I have to wonder if there’s something wrong with their data. (Might we be seeing gerrymandered counties?) Assuming there’s nothing wrong, that’s an awful lot of Democrats who will never meet a Republican!

Update: So why does this happen? Maybe it is all gerrymandered counties, or maybe it’s not. If not, what else is going on? Why are those results that way?

From → General

  1. Mary Messall permalink

    I would guess it somehow reflects the facts that 1) Most Democrats live in cities and 2) Most union members and other low-wage workers are still democrats. There must be lots and lots of counties that are all city, and mostly poor.

    But there are likely *not* very many at all that are both rural and rich. (Which is not to say that no poor people are Republican. The party is a strange coalition of poor, religious people, and wealthy Schwarzenegger types.)

  2. Thinking about it, my own county (Cook County Illinois, which contains much of Chicago) is probably part of that big Democratic spike. I do know lots of Chicagoans who’ve never met a Republican (which is fun for me, because I get to try to explain them, being from Kansas and being an extreme moderate by comparison to most people here). Chicago is pretty unusual with its history of Democratic machine politics, of course…

    But Cook has lots and lots of rich people, so I’d say what it is, is that the rich people who vote Democrat live in the same counties as the poor people who vote Democrat (if not the same neighborhoods) whereas the rich people who vote Republican live in different counties (suburban) than the poor people who vote Republican (largely rural). Result — lots of counties in which the rich and the poor vote Dem, so that the whole county effectively does, but few counties where both the rich and the poor vote Republican, resulting in greater division within Republican counties…

    But more of them, since most suburban and rural counties are likely to have one or the other, their rich or their poor, voting Republican.

    This is so interesting to speculate on that, if you don’t mind, I’m going to repost a lot of it on my own blog. I wonder if the polling data to support or disprove my hypothesis already exists?

  3. Suresh permalink

    Also check out

    for other maps and coloring schemes.

    I am not sure I completely understand their skew. visually it looks like a lot more regions are heavy bush than heavy kerry: maybe its a population count thing…

  4. steve permalink

    I think it would be most illuminating to see *which* counties were the ones that voted entirely Democrat. I’ll bet it’s only cities and university towns.

  5. Suresh permalink

    Hi Michael,
    Looks the michigan folks took their histogram down because of some errors. Here is another histogram with no skew in it:

  6. Yes, it was an error. The program which generated our histogram had a bug, so it mis-handled counties with spaces in their names, turning them all 99%+ for the Democrats. (In a word: Ooops.) But our map was produced by a different program, which doesn’t have that bug, so we’re rather confident it’s correct.

  7. Too bad the people running the US elections don’t have such bugs in their computer code…

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