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School Quality as a Cause of Racial IQ Gaps

Pupils In Class Using Digital Tablet

One environmental factor regularly brought up regarding racial IQ gaps is that some races go to “good schools” more often than others, and other races go to “bad schools” more often than others, and this would be one of the many explanations for racial IQ gaps. There are 4 reasons to believe that school quality has zero impact on racial gaps:

  1. The results of voucher studies
  2. The black-white IQ gap already exists BEFORE school
  3. Early intervention programs (“super school”) produce, at most, 2 IQ points, and these are radical, professional interventions that no normal family or school actually does in reality.
  4. Voucher Studies make the idea of “good schools” and “bad schools” dubious

A natural experiment on school quality exists in the form of voucher programs. In these programs, more students apply for the voucher than get them, and so the programs must pick and choose who gets the vouchers.

First they decided who was eligible based on whatever factors each program chose. Then, of the eligible students, they randomly selected those who got the vouchers.

And then the students who applied for vouchers and got them, and those who applied for vouchers and did NOT get them, were tracked. These were the Milwaukee Program, the Cleveland Program and the Washington DC Program

Milwaukee Program

Grade / Subject Voucher 06 Non-Voucher 06 Voucher 10 Non-Voucher 10
7 – Reading 432.2 435.3 492.2 485.4
8 – Reading 446.5 436.9 505.1 486.1
10 – Reading 458 472.9 493.5 492
7 – Math 388.2 395.7 501.6 500
8 – Math 426.3 424.4 504.2 493.3
10 – Math 462.9 478.7 515.5 524.2

Cleveland Program

Grade Voucher No Voucher Non-Applicant
1 555 546 548
2 587 577 580
3 615 605 607
4 632 620 624
5 643 636 636
6 654 639 638

Washington DC Program (voucher given at beginning of HS, tested at the end)

Math Reading
Voucher 641 645.92
Applicant 643.36 645.24

These 3 programs show that the variation in school quality – if such a variation even exists – between the schools voucher students chose and voucher applicants who didn’t get vouchers were stuck in, appears to have very little effect. Only the Cleveland program shows a consistent effect. However, the Milwaukee program also showed a positive effect from vouchers at that low grade.

The black-white IQ gap exists BEFORE school

The black-white IQ gap is fully formed by age 3. Jason Malloy of Humanvarieties.org looked at 48 studies, the earliest in 1939 and the latest in 2003 of black 3 year olds, and these were the means of all of those studies:

Decade Studies Mean
1960s and Prior 12 85.57
1970s 12 88.35
1980s 11 85.26
1990s and beyond 13 86.67

In addition, in the 24 studies in which there was a white group to compare to, the average IQ gap was 0.958 standard deviations.

Meaning that the black-white IQ gap appears to be almost fully formed by age 3 – which is almost the same as the adult racial IQ gap. In other words, the gap exists, in its near entirety, before school even begins. And the slight difference may just be a result of how performance varies at age groups.

One obvious counter to this is that “IQ at age 3 doesn’t mean anything”.

First off, there’s no real reason to believe this is true. We know that IQ at age 4 is a better predictor of adult IQ than the IQ of your parents is.

But beyond that, whether or not you think it “means anything” is irrelevant, because we’re talking about whether or not the later IQ gap is caused by differences in schools. And since the IQ gap is fully formed by age 3, and school doesn’t start until later, a difference in school quality is on it’s face an extremely unlikely explanation for the adult IQ gap.

Especially since these voucher studies directly compare the effects of “good schools” and “bad schools” – whereas in reality some blacks are in “good schools” and some whites are in “bad schools”, and so the difference in school quality between blacks and whites is probably not even as big as the differences in school quality in these voucher studies – which is probably zero anyway.

Early intervention (“super school”) has no lasting effect on IQ

meta-analysis written in May 2015 entitled “The environment in raising early intelligence: A meta-analysis of the fadeout effect” by John Protzko looked at 34 early intervention experiments (and 5 experiments on vitamin supplementation during pregnancy).

The studies, such as the Abecedarian Project, Perry Preschool Project, took children at a very young age and intelligence researchers were able to go whole-hog with all of their environmental theories about developing intelligence and how to develop it.

And with these, the most extreme forms of intervention, the researchers were able to raise the IQs of the participants by roughly 7 points, which faded out to 2 points 5 years after the intervention ended. The author writes:

Interventions that started earlier in a child’s life were no more effective than those which started later in a child’s life, nor did they affect how long the effects lasted (both ps N .15) and as such were dropped from the model. Duration played no appreciable role in explaining the fadeout effect and was also removed from the model.

Now this kind of early intervention is extreme and unrealistic, and can in a sense be treated as a kind of “super-school”, and a consistent 7 point improvement is big. Remember the black-white IQ gap is 15 points.

But also remember this gap exists by age 3, persists through school, and remains there into adulthood. This appears to be similar to the effects of exercising muscles – once you stop, your muscles go back to their “normal” level, which is why most of the variation in muscle between people is due to genetics as most people don’t lift weights.

And these radical early interventions – which are far beyond what any *real* family can provide – produce at most 2 points in terms of lasting effects, and probably not even that. There’s no good reason to believe that the differences in schools blacks and whites go to on average even approach the kinds of things done in these early intervention programs.