Tuesday, September 9, 2008

Democrat IQ Deficit Diminishing

Half Sigma has commented frequently on the downward trend of Republicans IQ as estimated by the WORDSUM variable in the General Social Survey (GSS).

While Half Sigma has identified the trend correctly, the numbers are presented in a somewhat misleading manner.His report looks at the raw numbers of scorers in each category and is therefore misleading because it doesn't reflect the proportion of people identifying with each party. Rearranging the numbers to reflect the percentage of people from each party falling into each category, we see a more accurate picture.

UPDATE: First, let's look at the average score from 1974 through 2010 and then we'll look at how the distribution has changed. This graph shows that the gap between Republicans, who tend to have higher IQ's and Democrats who tend to have lower IQ's has dropped on the GSS WordSum vocabulary test from 0.6 in 1974 to 0.3 in 2010.  The top of the blue line shows the average Republican score and the average Democrat score. The independents who expressed a preference are grouped with the party they favor. And yes, I color the Republicans blue. I'm sick enough of the left stealing terms like "liberal" and trying to stick us with their soiled words ("fascist"). Are we really going to let them swap colors with us just because they've soiled the term "socialist" the color that goes along with it?
Democrat IQ deficit (blue area) has been slowly diminishing
Let's consider two questions: why has this gap changed, and what happens if we look at the distribution of scores.

Initially, the Republican lead is a mirror image of the Democrat profile, with a nice linear progression with the highest number of Republicans scoring the "Smart" range and the highest number of Democrats scoring in the "Dumb Range".  If you plucked a random Republican and a random Democrat off the street in the early 70's, the odds where 13% greater that the Republican would score in the highest grouping on the vocabulary test than there is that the Democrat would do so.

So, then what happens? First, Reagan flattens the slopes slightly by drawing more of middle America into the Republican party:
Next, the Clinton years push more Democrats into smart category as Bill Clinton adopts a relatively free market economic approach with welfare reform, government downsizing, free trade agreements, and capital gains tax cuts:
Finally, in 2004, the perception that evangelicals control the Republican party and unhappiness with continued government growth cause the graph to change from straight lines into a barbell for the Dems and a hump for the Republicans:
So what does it all mean?  Republicans still have better vocabularies than Democrats, but the difference is entirely due to the disproportion number of Democrats and Independents scoring the bottom bucket.  In the upper range of scores the two parties have approximate parity.

I think we're seeing people in fancy suburbs align with the Democrats as a fashion statement. Bill Clinton's relatively conservative economics have erased the memory of Jimmy Carter and the fashion Democrats have not noticed that Harry Reid, Nancy Pelosi and Barack Obama hail more from the Jimmy Carter economic left rather than the more economic right under Clinton, especially during the latter Clinton years where the domestic policy agenda was determined by the conservative Republicans in the Gingrich revolution.

I'd also note the following data points from the GSS which persist to this day:
  • Republicans on average have more formal education than Democrats.
  • Republicans on average score higher on the vocabulary test than Democrats.
  • Conservative Republicans are verbally smarter and have more formal education than any other group.
One other note:  The GSS is a huge dataset, but using vocabulary as a proxy for IQ almost certainly understates how much smarter Republicans are than Democrats because it doesn't include questions testing the mathematical / visual component of IQ where Republicans tend to do better.

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