All across the country, applicants to graduate and professional schools have been receiving fat letters of acceptance or thin letters of rejection.

They have a right to feel nervous. They've sweated through college and through rigorous standardized exams, which they hope will open the door to their chosen professions. But the prestigious postgrad programs are ruthless about selecting the best candidates (at least if they are white or Asian). So, applicants obsess over whether their 165 LSATK-12 education or 680 GMAT is good enough to get in.

But, paradoxically, the faculty of the top schools seldom preaches what they practice when it comes to K-12 education or immigration. They are fiercely selectionist about who they let in to their institutions. Yet they lecture American citizens about how we should be lax about whom we let in to our country.

There is much that can be learned from the study of average test scores from the major postgrad exams. The idiosyncratic scoring systems do make them seem impenetrable to outsiders, but fortunately, they are all graded on the bell curve, so I've come up with a handy table that makes them easy to understand.

I've accumulated recent data on the average scores by race for five exams: the GRE for grad school, the LSAT for law school, the MCAT for medical school, the GMAT for business school, and the DAT for dental school.

To make all the numbers comprehensible, I've converted them to show where the mean for each race would fall in percentile terms relative to the distribution of scores among non-Hispanic white Americans. Most of us have some sense of what the distribution of talent is among whites—political correctness doesn't demand we avert our eyes when it comes to whites—so I'll use whites as benchmarks.

Thus, for example, on the Graduate Management Admission Test (GMAT), the gatekeeper for the M.B.A. degree, the mean score for whites falls, by definition, at the 50th percentile of the white distribution of scores. The mean score for black test-takers would rank at the 13th percentile among whites. Asians average a little better than the typical white, scoring at the 55th percentile.

Most of these tests break out separate nationalities among Hispanics. Thus, my table has columns both for "Total Hispanics" (27th percentile on the GMAT) and "Mexican-Americans" (24th percentile). In the 2000 Census, Mexicans made up 58 percent of the Total Hispanic population.

I listed the subtest scores for the Graduate Record Exam (GRE) and Medical College Admission Test (MCAT) because the sources didn't aggregate them.

Note that language is a surprisingly small problem for Hispanics—they score no worse on the GRE Verbal subtest than on the GRE Quantitative, and only moderately worse on Verbal portion of the MCAT. Why? Because Hispanics who have problems with English generally don't finish college, or even high school.

As you'll note, the black average scores are consistently low across all five tests, plus the listed subtests. The scores for Asian Americans are generally good, but they bounce around depending upon the balance of verbal vs. quantitative / visual questions. The Total Hispanic and Mexican-American scores are dependably mediocre—better than blacks, worse than whites.

If we look at how many people of each group take the test, we can understand the variations in average score a little better.

Thus, for example, whites, who in 2007 made up 61.5 percent of the 20-24-year-old cohort, took 68.7 percent of the GMATs. Blacks took the GMAT at a per capita rate just under half (49 percent) of the white rate. Asians are more than twice (205 percent) as likely as whites to sit the GMAT. Mexicans are only a fifth (18 per cent) as likely.

(If you are wondering why America's white elites aren't more worried about their kids facing competition from the huge number of Mexican immigrants they've let in, this educational indolence is one answer—at the highest levels of American society, Mexican-Americans just aren't much competition.)

We are often lectured about how our racist society crushes the fragile self-esteem of African Americans. But this combination of average score and sample size data suggests that blacks tend to have inflated ambitions, especially compared to the under-ambitious Mexican American population.

I don't know how many times I've heard a poor black child interviewed on TV say "I want to be a doctor or a lawyer when I grow up" while the television personality nods encouragingly. But it's many more times than I've heard a poor black child say, "I want to own my own carpet-cleaning business when I grow up".

Consider the Law School Admission Test. Blacks made up a sizable 10.3 percent of LSAT-takers in 2006, while Mexican-Americans comprised only 1.6 percent, barely up from 1.1 percent way back in 1985. This large number of black law school hopefuls suffered from diminishing marginal returns: their mean score equated to just the 12th percentile among white test-takers.

In contrast, Mexican Americans scored at the semi-respectable 29th percentile among white. That was because only an elite few out of their ranks dared take the LSAT at all. If more Mexicans had tried it, their average would likely have been lower.

What nobody tells those black children is that even if you get into medical school or law school, you still have to pass a professional licensing exam when you get out.

Data gathered by Richard Sanders of the UCLA Law School shows that 53% of the black students who enter law school fail to qualify to become lawyers, versus 24% of white students. About 40 percent of black law school graduates (many of whom will have taken out crushing loans to pay three years of tuition) never pass the bar exam, compared to 15 percent of whites. Some will also waste additional years working dead-end day jobs while paying to take bar exam review courses at night, before finally giving up in despair.

In effect, the legal establishment is luring a sizable number of the black race's more promising young people (not the very best and brightest blacks, but well above average African Americans) into a career cul-de-sac. That warm and fuzzy feeling that liberals get from "diversity" comes with very real human costs.

You'll notice that blacks take all five tests at relatively similar rates, while Asians specialize in the medical professions and tend to avoid grad school (probably because it prepares for generally lower paying careers). In a diverse society, it's natural for racial groups to specialize in certain occupations the way Asians do. Yet, blacks don't. One reason for that: blacks are counted as "diverse" for affirmative action purposes, while Asians generally aren't. The grad schools' institutional hunger for black students means that blacks aren't allowed to develop ethnic specialties.

You might think, for instance, that blacks would be more inclined to take the DAT to try to get into dental school than the MCAT for medical school. After all—and this is not intended as an insult to dentists: the DAT User's Manual testifies to the enormous effort the American Dental Association has put into making the DAT an extremely rigorous 4.5 hour-long test—studying one part of the body is surely less daunting than studying all of it.

But instead, blacks are relatively more likely to take the MCAT (where they do very badly: about the 11th percentile) than the DAT (where they face somewhat less competition and score at the 16th percentile). 

Yet what would be the reaction of American Association of Medical Colleges and the American Medical Association if a healthy trend developed in which blacks focused more on dental than medical school?

A national crisis would be declared! The medical community would be instructed to mobilize its vast resources to fight off the challenge from dentists for precious diverse students! Bidding wars for blacks would get even more flagrant!

And the Law School Admission Council is probably even crazier for diversity than the medical colleges.

In short, none of these powerful institutions will allow blacks to develop their own specialties. All of them compete against each other for scarce black talent. This is not because they care about blacks, because (as we've seen) many of blacks are burned out by being mis-selected.

Many blacks might be better off going to business school than to law or medical school because you don't have to pass a licensing exam afterwards. You just get your diploma and put "M.B.A." on your resume. (How much that's worth is, however, another question altogether.)

It's just another example of the intra-white status game. To adapt what I wrote some time ago: what white admissions officers in grad schools care about "is achieving social superiority over other whites by demonstrating their exquisite racial sensitivity and their aristocratic insouciance about any competitive threats posed by racial preferences."

Our culture doesn't give practical advice to young blacks—because it would be "racist".

[Steve Sailer (email him) is movie critic for The American Conservative. His website www.iSteve.blogspot.com features his daily blog. His new book, AMERICA'S HALF-BLOOD PRINCE: BARACK OBAMA'S "STORY OF RACE AND INHERITANCE", is available here.]