Red/blue/rich/poor: 2008 update

November 25th, 2008, by Andrew

In our book, we discussed how the rich-state, poor-state divide was larger among the rich than the poor–or, to put it another way, how rich people in states such as Mississippi are much more Republican than poor people in Mississippi, but rich people in Connecticut do not vote so differently from poor people in Connecticut.

What happened in 2008? From the exit poll data at the CNN website, we get:

On the logarithmic scale:

The x-positions of these lines are in different places because Mississippi and Connecticut got small samples and CNN didn’t post the percentages for some of the extreme categories which had small n’s.

Here are three states ranging from Texas (strongly Republican) to Florida (battleground) to California (strongly Democratic). Texas actually has a higher per-capita income than Florida, but here are the exit poll data in any case:

The more systematic thing to do is to look at all 50 states. In each, I took McCain’s share of the two-party vote for each income category where we had data, then regressed it on the category numbers (which we originally numbered 1 through 8 and then standardized to have mean 0 and standard deviation 0.5). I then plotted these regression coefficients on a graph along with state income:

The y-scale of the graph roughly represents McCain’s vote share among the rich minus his share among the poor, within the state. We see the familiar pattern from our book, that the association of rich with Republican holds everywhere but is strongest in poor states. The states are colored as red or blue where McCain or Obama won by more than 10% of the two-party vote, and purple for the states in between.

But there’s a potential problem here, as illustrated by the Mississippi-Connecticut pattern above. The data from Mississippi are more at the low end of income, and the data from Connecticut are more at the high end. We already know that the relation between income and Republican voting flattens out at higher incomes, and so maybe Connecticut’s flat slope arises just because we’re taking its numbers from the flatter part of the curve.

To correct for this, for each state we take the regression plotted above, then we fit the same regression to the same range of incomes from the national exit poll, then we add back in the full regression of the national poll using all eight income categories. The result is a quick estimate of what the entire difference between rich and poor would be in the state, if we were to have sufficient data from all eight income categories within each state.

And here’s the result:

A few of the southern states on the left part of the graph have high rich-poor voting differences (even after controlling for the range of incomes where the comparisons were being made), but the overall pattern of rich and poor states isn’t so strong.

Further thoughts:

1. Larry Bartels comments that if you only look at whites, the rich voter, poor voter pattern is similar in rich and in poor states. So one of our main findings from the Red State, Blue State book from the 2000 and 2004 elections did not persist in 2008.

2. Boy do I want the raw exit poll data so I don’t have to screw around with these artificial missing data problems.

3. I also want some pre-election poll data. The exit polls were so screwed up this year, I don’t fully trust anything based on exit poll data alone.

Similar Posts:

• In 2008, Rich States Vote Democratic, Poor States Vote Republican — Again
• More on red/blue/rich/poor in 2008
• Trends in income inequality within and between states
• 2004/2008
• Election 2008: what really happened

Entry Filed under: Uncategorized