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:
- The results of voucher studies
- The black-white IQ gap already exists BEFORE school
- 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.
- 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
|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|
Washington DC Program (voucher given at beginning of HS, tested at the end)
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:
|1960s and Prior||12||85.57|
|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”.
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
A 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.