Saturday, October 21, 2006

Black IQ estimates by state

Employing the same methodology used to estimate state average IQs, I've been breaking the results down by race. Black estimates by state follow (those not listed had too small an NAEP test-taking contingent to use with any statistical certainty):

1) Washington -- 94.5
2) Delaware -- 93.9
3) Massachusetts -- 93.6
3) Virginia -- 93.6
5) Alaska -- 93.5
6) New Jersey -- 92.9
7) Colorado -- 92.9
8) South Carolina -- 92.5
9) New Mexico -- 92.3
10) Kentucky -- 92.2
11) Texas -- 92.2
12) New York -- 92.1
13) Oregon -- 92.0
14) Arizona -- 91.9
15) North Carolina -- 91.5
16) West Virginia -- 91.5
17) Georgia -- 91.3
18) Iowa -- 91.3
18) Kansas -- 91.3
20) Maryland -- 91.2
21) Ohio -- 91.1
22) Michigan -- 91.1
23) Conneticut -- 90.6
24) Indiana -- 90.4
25) Pennsylvania -- 90.4
26) Missouri -- 90.4
27) Rhode Island -- 90.2
28) Louisiana -- 90.1
29) Minnesota -- 90.0
30) Illinois -- 89.8
30) Oklahoma -- 89.8
32) California -- 89.7
33) Florida -- 89.6
34) Wisconsin -- 89.5
35) Tennessee -- 89.3
36) Nebraska -- 89.0
37) Nevada -- 88.7
38) DC -- 88.6
39) Mississippi -- 88.5
40) Arkansas -- 88.0
41) Alabama -- 87.8

The relatively high scores jump out immediately to those who are familiar with the historical results of IQ testing by race. Adjusted for population, the average IQ estimate for black Americans comes to just under 91. Traditionally, African Americans have consistently scored around 85, and the gap between whites and blacks has held tenaciously at one standard deviation. So these estimates appear rather high. A few possibilities as to why:

- The black/white IQ gap may be narrowing. Flynn and Dickens argue that blacks have gained five or six points on whites over the last three decades, presumably spurred in part by better access to nutrition and healthcare. If accurate, that would put contemporary average African American IQ at 90 or 91, just as my estimates did.

- The rate of interracial marriage and procreation has increased over time. Lynn marshalls lots of evidence showing that racial 'hybrids' tend toward IQs that are an average of the two groups their parents represent. The offspring of one black and one white parent represent almost 3% of American births today, compared to about 2.3% in 1995 and around 1.3% in 1980. This should work to attenuate the gap by slightly lowering average white IQ and raising average black IQ a bit (the latter should rise more than the former falls due to sheer size). But taking a net 1.7% 'blending' and assuming a 15 point gap would only be expected to narrow the gap by a quarter of one point.

Relatedly, states with lighter skinned blacks (those with more white ancestry in the northern states especially) tend to achieve higher test score results, although the results aren't that pronounced. Deep-south South Carolina certainly bucks the trend, probably due to the number of black military families at Fort Jackson, where most army personnel are initially trained.

- I built the formula for the estimates using Lynn's data on international academic and IQ test results, so my equation is linear. Although Lynn believes that adjusting for attenuation yields a correlation between test scores and IQ of 1 (a perfect relationship), I'm inclined to assume that the correlations for IQ and math (.87) and IQ and science (.81), even adjusted for attenuation, are still not perfect. And because my formula is linear, moving further out from the averages if anything underestimates the magnitude of the true deviation. So depending on the true strength of the relationship, the estimates might be inflated by a couple of points (although I think this would only be on the order of a point or two).

- Differing rates of truancy by race may be artificially giving blacks a boost relative to whites. Assuming that children frequently absent from school generally come from more chaotic, less endowed households, it follows that students who are the least likely to show up on test day are among the poorest performers. And the absentee rate for black children (24%), defined as missing an average of three or more days per month, is greater than the rate for white striplings (19%).

- According to Rushton, black adolescents develop faster than white adolescents (who in turn develop faster than Asians). Consequently, young blacks achieve greater parity with their white counterparts than they do as both groups age. Indeed, very early on black children may be more intelligent than whites and Asians due to relatively accelerated physical development. This meshes with Steve Sailer's tentative assertion and the GNXP graph supporting it that the gap may have narrowed among children but doesn't appear to be shrinking among adults. To the extent that differing development levels affect average scores by race, IQ tests based on an average white IQ of 100 given to children will tend to underestimate the eventual cognitive capacity of Asians and overestimate it for blacks.

(Human biodiversity2)


JSBolton said...

"Estimating the IQ of states of the USA
posted by Dienekes on Tuesday, October 17, 2006"
Have you seen this, and how well do you trust the data if you have?

crush41 said...

Thanks for pointing that post out John. I'll have some fun correlating my estimates and the paper's estimates against different factors and seeing how they relate and match up with one another.

My first impression is that the IQ scores estimated by the paper Dienekes references are quite high. Texas, without a white majority and virtually no Asians still has an average IQ of 100? Delaware, at 20% black and with mediocre whites (by NAEP scores), scores over 100? I'm incredulous for now.

Steve Sailer said...


Anybody know what the problem is with Milwaukee blacks? They always show up toward the bottom of black rankings, even though northern blacks usually outperform southern blacks.

Anonymous said...

I'd be interested to see the average IQ for Asians by state. I'm guessing Hawaii would score the lowest, while a state on the East Coast would score the highest.

crush41 said...


I've pondered that as well. Could it be that there has been some black middle class flight from the upper midwestern states as the economies there have soured (Wisconsin fares especially poorly, but blacks in Minnesota, Ohio, Michigan, and Illinois don't do particularly well either as compared to blacks in nearby states like Iowa, Kentucky, or Virginia)?


Unfortunately the data from NAEP on Asians is pretty limited. Your intuition is right about Hawaii though. If memory serves, the state has the worst Asian scores in the country (I will post estimates using the limited Asian data in the future).

Tino_G said...

Isn't the high "IQ" estimate for blacks because these are not IQ, but in some part school results?

Bearded Malcontent said...

Are you using the grade 12 data? Then it's not very representative since blacks are more likely to drop out by then.

crush41 said...


I'm basing the estimates on the relationship between IQ and both international math and science tests that Richard Lynn found in his book Race Differences in Intelligence.


I used strictly eighth grade NAEP results. The number of students who have dropped out by that time is marginal, although they (like the truants) are probably of a lower academic class than the average.

Anonymous said...

Have you done a county by county IQ estimate?
Does it match the NYT map of subprime loans they posted recently, noting that minorities have a higher percentage of subprime loans?

Anonymous said...

The NYT subprime mortgage map can be seen here:

Anonymous said...

The average black IQ in the US is 85. The average black IQ in the deep south is 80. At 80, when the supervisor leaves, the work stops....

mr_evergreen said...

One major thing that hasn't been considered is ethnicity. Washington and Massachusetts have sizable populations of foreign-born Blacks.

Also consider profession. Boston and Seattle are major tech centers. I would imagine Blacks working in those industries would be those who have more intellectual prowess.

As for North vs South, I see this pattern. 90 percent of Blacks lived in the South in 1900. During WWI, Blacks from Ohio scored higher on mental tests than Whites from Kentucky. What is the difference between then and now? The Great Migration. Many Blacks with little education went North to work in the factories. Culture is an important factor. Blacks with roots in the North were exposed to a different culture, a different way of doing things. Southern underclass culture was very detrimental to Whites and damaging for Blacks. The "ghetto" culture seen in the Black underclass is really "redneck" subculture transplanted to the cities. Blacks who escaped this culture did so via education, which led to a better way of living. Those who didn't, well, the price was steep. I think this would explain Milwaukee. Much of Milwaukee's Black population came from 1950 and after, and mainly from the rural parts of the South. I suspect those who are doing very poorly in Milwaukee aren't that far removed from the South, in terms of generations. I would read Thomas Sowell's "Black Rednecks and White Liberals" in order to get an understanding in the difference between southern culture and northern culture.