Smart Democrats?

Prior to the election I read numerous essays claiming that Democrats are smarter and more educated than Republicans. For example, I received the following email from a friend:

OK, call me an elitist but this is disturbing:

Bush's Chief Advisor, Karl Rove has already said it: "As people do
better, they start voting like Republicans...unless they have too much
education and vote Democratic, which proves there can be too much of a
good thing." http://www.dailykos.com/story/2003/10/16/10516/074

Here's a chart that clearly indicates how stupid Republicans are
compared to Democrats...

I won't reproduce the chart here, but it shows the percentage of people with college degrees was higher in states that voted for Gore in 2000 than in those states that voted for Bush. What it doesn't show, and what doesn't seem to be true, is what the emailer claims: that Democrats are smarter than Republicans.

The problem is that a fairly complex multivariate analysis with far more data would be required to show that there is a relationship between state by state voting patterns, percentage of college graduates, and intelligence of voters based on who they voted for. To illustrate this, consider the following: let's say there are two states, state A and state B, that have identical distributions of intelligence within their respective populations. But let's say state A was poorer. Which state would you guess had more college graduates? I'd guess B. Let's say state A had a higher percentage of jobs in agriculture and manufacturing. Which state would you guess had more college graduates? I'd guess B.

There are numerous other factors as well. Average age of the population, ethnicity, state government grants for college education, etc. The influence of all of these other factors could easily outweigh an intelligence factor, if the intelligence factor exists at all.

So lets look at some more direct data. A quick look at exit polls tells us education levels for those voting for Bush relative to his opponents are very similar:

A more direct comparison of the parties' voters can be found in the 2000 exit poll, where Bush voters reported an average educational level negligibly greater than Gore voters. Gore did best among high school dropouts and those who had undertaken post-graduate studies, with Bush leading among those in-between. (Many Democrats with advanced degrees, by the way, are public school teachers with credentials in the easy field of Education.)

In the 2002 midterm elections, voters supporting Republican House candidates were particularly well-educated. The GOP won 58% - 40% among college graduates and even captured a majority among postgrads for the first time in many years.

In 2004, Bush's majority was more downscale. If you assume that high school dropouts averaged 10 years of schooling, high school grads 12 years, those who attended college but didn't graduate 14 years, college grads 16, and postgrads 18, then Kerry voters claimed 14.64 years of education and Bush voters 14.48 years, or only about six weeks less schooling.

Exit polls are notoriously unreliable, though, and I've heard it claimed that people tend to overstate their education level. However, there is no evidence that I've found that Republicans systematically overstate their education level more than Democrats, though anything is possible.

An interesting note is that white Bush voters do seem to be somewhat less educated, on average, than white Kerry voters:

White Voters:
High School Grad: 62% Bush
Some College: 61% Bush
College Grad: 58% Bush
Some Postgrad: 48% Bush

From this we can compute that the average white Bush voter had 14.6 years of school versus 15.0 years for white Kerry voters. This represents a difference of a little less than 5 months of school. However, I don't think white Kerry voters can take too much comfort in this since there were still significantly more white Bush college graduates than white Kerry graduates.

What about IQ studies? IQ is considered by some people to be the most direct measure of intelligence. I personally don't believe that IQ is particularly useful as a measure of intelligence except as a measure of relative intelligence within a very homogeneous subpopulation. Nonetheless, let's look at IQ and voting.

The Economist (May 15, 2004, p. 26) published a chart showing the average IQ of each state with Connecticut having a stratospheric 113 average IQ down to Mississippi having and subterranean average IQ of 85. The Economist printed a retraction in a subsequent issue after they realized they had fallen for a hoax. However, that same chart can be found on thousands of sites across the Internet and still appears in the mainstream media from time to time.

There has not been a nationwide IQ study with appropriate sampling by state. The best that can be done is to use SAT, ACT, or NAEP math and reading scores as a proxy for IQ and intelligence. There are numerous analyses. My favorite is this one. The bottom line is that there is no nationwide correlation of someone's IQ with which presidential candidate that person voted for. As I wrote here, it may be that very conservative Republicans and very liberal Democrats are more educated, on average, than more moderate members of both parties. Lastly, just like education, white Kerry voters were, on average, more intelligent than Bush voters. However, since many more white voters voted for Bush, significantly more above average intelligence white voters voted for Bush than Kerry.

In summary, the data does not support statements to the effect that Democrats are either more intelligent or more educated than Republicans. While there is some evidence that white Kerry voters are on average more intelligent and educated than white Bush voters, a majority of college graduates and a majority of above average intelligence voters voted for Bush.