Among whites, 82% were said to be white by at least four of the five listeners. Grogger calls these the "distinctly white" group. The other 18% were grouped as "indistinctly white." ("Indistinctly White" reminds me of Onion Opinion essayist Amber Richardson, author of "Why Somebody Always Around Everytime I Drop my Baby?")
Among blacks, 67% were "distinctly black." Grogger has the U.S. Military's ASVAB scores for all NLSY participants (although of the 10 ASVAB subtests, the most interesting are the four that make up the very IQ-like AFQT, but he doesn't report those). Converted by me to a conventional IQ scale with the national average at 100 and a standard deviation of 15, here are the ASVAB scores:
The final column indicates that the mean ASVAB score for blacks is 0.85 standard deviations lower than the mean for whites. This is similar to the racial differences that appear in many standardized tests (Jencks and Phillips, 1998).
Indistinctly identified whites score 0.16 standard deviations lower on the ASVAB than distinctly identified whites. The difference is greater for blacks. Distinctly identified blacks score .66 standard deviations lower than indistinctly identified blacks. It should come as little surprise that test scores differ between distinctly and indistinctly identified blacks, since test scores factored into the definition of the two groups.
What is surprising is the magnitude of the difference. To put it in perspective, the gap between distinctly and indistinctly identified blacks amounts to three quarters of the gap that exists between blacks and whites.
Similarly large differences appear in years of schooling. Mean highest grade completed among indistinctly identified whites is 12.49 years, compared to 13.22 years among distinctly identified whites. Again, the gap is larger for blacks. The difference in mean highest grade completed between distinctly and indistinctly identified blacks is 0.9 years. This is larger than the gap of 0.83 years between blacks and whites overall.
Keep in mind that the respondents are in their early to mid-20s, so many haven't finished schooling.
Table 7 presents the relationship between speech patterns and ASVAB scores somewhat differently. For each quartile of the ASVAB distribution (within the speech sample), it presents by race the share of speakers whose race was distinctly identified by listeners. The first column shows that the link between speech patterns and ASVAB scores is quite weak for whites. With the exception of the lowest ASVAB quartile, 81 to 84 percent of whites were distinctly identified as white. In contrast, the link between speech patterns and ASVAB scores is quite strong among blacks. In the lowest quartile, 82 percent of black speakers were distinctly identified. That share declines monotonically by quartile to a low of 25 percent among those at the top.
There are only 8 blacks in the top quartile of ASVAB scorers, but 6 of them didn't sound distinctly black. In contrast, of the 45 blacks in the bottom quartile of test scores, only 8 of them didn't sound distinctly black.
Together, Tables 6 and 7 show that skill and speech patterns are highly correlated among black speakers. At the same time, the correlations among white speakers are much weaker.
His main finding: blacks who “sound black” earn salaries that are 10 percent lower than blacks who do not “sound black,” even after controlling for measures of intelligence, experience in the work force, and other factors that influence how much people earn. (For what it is worth, whites who “sound black” earn 6 percent lower than other whites.) ...
In other words, Grogger has already adjusted for the big IQ gap between distinctly black and indistinctly black panelists, and there's still a wage gap.
(It turns out you don’t want to sound southern, either. Although pretty imprecisely estimated, it is almost as bad for your wages to sound southern as it is to sound black, even controlling for whether you live in the south.)
Unfortunately, Grogger appears to be lumping white and black Southerners together, which isn't that helpful.
And no, he doesn't tell us what the average IQ of whites who sound Southern is. I noticed when I was at Rice U. in Houston that a couple of my classmates had siblings attending local colleges who sounded much more Texan than they did.
Whether black or Southern, it's part of the homeboy phenomenon. Using a neutral national accent suggests you are willing to do what it takes to get ahead in this country, while using a subgroup accent suggests you are loyal to the values of your neighborhood and aren't as willing to make sacrifices.