Bruce G. Charlton suggested cognitive parity might also be good for the GOP. From the limited correspondence I've had with him, I've found that when he suggests something, it's worth investigating.
The National Assessment of Educational Progress (NAEP) provides a way of doing so. The Department of Education's NCES site has recently been updated to allow for a wide range of statistical comparisons to be made among states and territories. In addition to providing average state level scores by subject, by year, and by race, the NAEP site can be queried for standard deviations on the same. The wider the standard deviation, the greater the cognitive disparity in the state.
Following is a table ranking the states by cognitive disparity as measured by state-level standard NAEP math and reading scores for 8th graders in '07, the latest year for which there are available data. Both tests are on a 500 point scale. The nationwide standard deviation was 35 points for reading and 36 points for math. The table reports an average standard deviation value from the '07 tests:
|Hawaii, Rhode Island||36.5|
|DC, Florida, Michigan, North Carolina, Washington||35.5|
|Alaska, Maryland, New Jersey, New York, Oregon,|
|Arkansas, Illinois, Pennsylvania, South Carolina||34.5|
|Colorado, Minnesota, Missouri, Nebraska, West|
Georgia, Indiana, Iowa, Massachusetts,
|Idaho, Kentucky, Mississippi, Texas, Virginia||32.5|
|Delaware, Oklahoma, Vermont||32|
|Kansas, New Hampshire, Wisconsin||31.5|
|Louisiana, Maine, Montana, South Dakota||31|
The size of a state's standard deviation on its NAEP average scores and it's level of support for McCain is an inverse .36 (p=.01). A state's SD and it's level of support for Bush in '04 is a similar .37 (p=.01)*.
The wider a state's intelligence distribution is, the bluer that state tends to be. In addition to inequalities in educational attainment and wealth, inequalities in IQ are also good for the Democratic party. So the party putatively determined to reduce inequality benefits from doing just the opposite, while the party putatively more tolerant of cutthroat competition and the winners and losers it produces benefits not from economic wins and losses but from draws. This seems to provide some justification for the general sense that red states (especially outside the South) tend to be less chaotic and intrusive places to live, but also tend not to be on the cutting edge of technological or cultural trends, either.
The variances in score distributions is not the result of blue states being more intelligent than red states are, as might be anticipated. There is no relationship between a state's average IQ and voting patterns in Presidential elections**.
The 10.5 point range for the states is not huge, but that does not mean it is not important. California's standard deviation is more than one-third larger than North Dakota's is. Presuming for simplicity that both states' average IQ is 100 and that a 15 IQ point standard deviation is the national standard deviation of 35 for reading, a person with an IQ of 112 is in the 84th percentile in North Dakota, while a person must have an IQ of 117 to be in the 84th percentile in California. Conversely, an IQ of 88 would put a person in the 16th percentile in North Dakota, but it would require an IQ of 83 to be similarly placed in California. California would thus have relatively more of both smarties and dummies running around than the more middling North Dakota would (in reality, as North Dakota's average IQ is, presuming a standard intelligence distribution, half a standard deviation higher than California's is, so in reality California probably has relatively more uber-smarties, dummies, and uber-dummies than North Dakota does).
After realizing the above, I presumed the relationships would be stronger when only white students and white voters were considered, but they are nearly the same as when the entire population is considered. In fact, they're a little weaker. The correlation between NAEP SDs by state and support for McCain is .29 (p=.04). For NAEP SDs and support for Bush, it's .37 (p=.01). The potential strength of these relationships appears to be weakened by the fact that white state-level variances in the South and Midwest are similar, but white support for the Republican candidate is firmer in the former than the latter.
Via Swivel, the data are here.
* The state's aggregated standard deviation used in comparison with the '08 election is computed by finding the state SDs for both the '07 reading and '07 math tests and averaging them. The same is done using reading and math tests from '03 for comparison with the level of Bush support in the '04 Presidential election. It was my intention to use writing and science assessments to create a 'deeper' aggregated SD average, but neither assessment receives full participation by all 50 states and DC. But being able to utilize assessments in math and reading allows for reasonable confidence that both verbal and non-verbal aspects of IQ are being measured.
Parenthetically, this is presumably one reason VCU's Professor McDaniels' used NAEP scores for math and reading to comprise his average IQ estimates by state. Previous estimates were made here that correlated almost perfectly with his, although I used math and science scores. Consequently, for a couple of states I had to rely on math scores alone.
** Given the South's support for the GOP, this might come as a surprise. Remember, though, that as overwhelming as the white vote in the South is for the Republican candidate, significant black support for the Democratic candidate means that the strongest levels of total GOP support tend to come not from Southern states but from states in the heartland, like Oklahoma, Wyoming, and Utah (the three most Republican states in '08). Further, several of the most reliably Democratic states are not the sharpest of the blue. Among the top ten blue states in '08--DC (#51), Hawaii (#48), Vermont (#3), Rhode Island (#37), Massachusetts (#1), New York (#30), Maryland (#34), Illinois (#31), Delaware (#23), and California (#46)--only two are in the upper echelons of average state IQ.