I’ve discussed this before but given that I now have better data on the old SAT, I thought I’d revisit it.
Because the SAT has generally only been given to the college bound elite, nobody really knows how well it correlates with IQ in the general U.S. population.
But because it’s generally assumed that roughly 100% of Americans capable of scoring very high on the SAT actually take the SAT, I decided that the best way to estimate the SAT’s correlation with IQ among all American young adults is to find a subset of Americans selected for extremely high SAT scores and then see how they score on official IQ tests.
Because people selected for high SAT scores will regress to the U.S. mean on IQ in direct proportion with the correlation between the SAT and IQ in the full U.S. population (if all Americans young adults took the test), I use the degree to which they regress as an estimate for said correlation (assuming a bivariate normal distribution).
Perhaps the single best study was referred to me by a commenter named Andrew. In this study, data was taken from the older more difficult SAT, and participants took the full-original WAIS. In this study, six samples of seniors from the extremely prestigious Dartmouth (the 12th most selective university in America) averaged 1357 on the SAT just before 1974. Based on my latest research, an SAT score of 1357 if all American 17-year-olds circa 1974 had taken the SAT, the mean score would have been 770 (SD = 223) which means 1357 would have equated to an IQ of 139 (U.S. norms); 138 (U.S. white norms).
Assuming these students are typical of high SAT Americans, it is interesting to ask how much they regress to the mean on various subtests of the WAIS.
Averaging all six samples together, and then adjusting for the yearly Flynn effect from the 1950s through the 1970s (see page 240 of Are We Getting Smarter?) since the WAIS was normed circa 1953.5 but the students were tested circa 1971.5, then converting subtest scaled scores to IQ equivalents, in both U.S. norms and U.S. white norms (the 1953.5 norming of the WAIS included only whites), we get the following:
| iq equivalent (u.s. norms) | iq equivalent (u.s. white norms) | estimated correlation with sat in the general u.s. population inferred from regression to the mean from SAT IQ 44 points above U.S. mean. | |
| sat score | 139 | 138 | 39/39 = 1.0 |
| wais information | 128.29 | 127.2 | 28.29/39 = 0.73 |
| wais comprehension | 122.22 | 120.9 | 22.22/39 = 0.57 |
| wais arithmetic | 120.37 | 119 | 20.37/39 = 0.52 |
| wais similarities | 119.16 | 117.75 | 19.16/39 = 0.49 |
| wais digit span | 117.37 | 115.9 | 17.37/39 = 0.45 |
| wais vocabulary | 125.93 | 124.75 | 25.93/39 = 0.66 |
| wais picture completion | 105.87 | 104 | 5.87/39 = 0.15 |
| wais block design | 121.82 | 120.5 | 21.82/39 = 0.56 |
| wais picture arrangement | 108.33 | 106.55 | 8.33/39 = 0.21 |
| wais object assembly | 113.65 | 112.05 | 13.65/39 = 0.35 |
| wais verbal scale | 126 | 125 | 26/39 = 0.67 |
| wais performance scale | 116 | 114 | 16/39 = 0.41 |
| wais full-scale | 123 | 122 | 23/39 = 0.59 |
Conclusion
The degree of regression from the SAT to the WAIS in an extreme sample suggests a 0.59 correlation between the two tests in the general U.S. population.
The SAT seems to be a reasonable proxy for verbal IQ (an implied correlation of 0.67) but only a moderate proxy for performance IQ (an implied correlation of 0.41). There are generations of visually brilliant people who did not get into a good college thanks to the SAT, but nonetheless may have earned high incomes as artists, tradesmen, fashion designers and film makers.
Not surprisingly, the SAT correlated best with the Information and Vocabulary subtests (implied correlations of 0.73 and 0.66 respectively) since these are direct measures of facts taught in school.
The real question is how well does the SAT correlate with g (the general factor of IQ tests)
Arthur Jensen argued that the correlation between two tests is a product of their factor loadings, so if the WAIS correlates 0.9 with g, and correlates 0.59 with the SAT, then the SAT should correlate 0.59/0.9 = 0.66 with g.
However since the SAT and WAIS share other factors besides just g (i.e. verbal), then 0.66 might overestimate the g loading.
On the other hand some would argue that deducing the regression slope from only high ability people might underestimate the correlation between the SAT and WAIS (ceiling bumping, Spearman’s Law of Diminishing Returns), and correcting WAIS scores for the Flynn effect might be overcorrections particularly at the high end.
Perhaps both factors cancel out, leaving 0.66 as a good estimate of the SAT’s g loading in the general U.S. population.
Is the SAT an IQ test?
If one defines an IQ test as any psychometric test with a high g loading in a general national or global population, and if one defines a high g loading as 0.7+, I’d say the SAT is a borderline IQ test.
Pumpkin Person 
WAIS correlates 0.9 with g, and correlates 0.59 with the SAT
Animekitty 130 g
wais 0.9 * 30 g = g 27
wais 0.59 * SAT-IQ 55 = g 32.45
29.725 = (27 + 32.45)/2
very accurate
exactly matches my g score 130.
But
0.66 * 55 = 36.3
my g might be as high as 36.3
officially I have a (g) of 130
So Asian are willing to have a test enforced even if it’s racially biased against them (vesus Jewish or Black people who’s intelligence suits the test best)
SAT and IQ are different versions of each other. They contain general knowledge questions. No surprise that it has a high correlation and the ‘g’ loading is built into the IQ tests through test construction.
working memory and processing speed are least correlated with (g) somewhere around 0.3 coefficient. Yet the ability to hold information in your head and quickly work on it/absorb it, is considered the most culture fair measurement of intelligence.
But in terms of (g) the ability to absorb cultural knowledge and utilize spatial/visual ability is not wholly due to exposure. Take language where some people are just able to get good at it quicker. Or drawing where they were good at it and some were so good that made it their main focus. If you are good at something you will do it more and (g) shows that people can excel at perceptual reasoning and verbal strengths so much so that those with greater ability will improve faster. A person that has little ability in these areas will do something else not because they have little exposed but generally have little ability to move on to higher levels due to little ability.
You really should [redacted by pp, june 18, 2017]because all you are doing is coming to this subject from a place of ignorance in all this.
Everyone has their own pet definition of “intelligence”, what matters is construct validity.
Im not “coming from a place of ignorance in all this”, I used to be a “hereditarian”, my views changed.
It doesn’t change the fact that ‘g’ is built into the test by the rest constructors.
I should really what? Why did you react that PP? I’m an adult.
I’ll tell you by email. It wasnt anything offensive. That’s not why i moderated it
Too bad there was no Matrix Reasoning tesg, which is probably the best performance test.
This seems to suggest your 122 estimate for Harvard was too low. Maybe closer to 128?
Is there any difference between an IQ of 109 and 110, or 114-115, or 129-130? Is there any difference between 110-120 or 115-125? Also, if someone was good at math (figure weights subtest), but bad at spatial stuff (Block Design and Visual Puzzles), would their real IQ be somewhat skewed because figure weights is not a main subtest?
Also, why aren’t there norms for bilingual Americans, for the Verbal Subtests?
”Is there any difference between an IQ of 109 and 110, or 114-115, or 129-130? Is there any difference between 110-120 or 115-125?”
There is
What are the qualitative differences?
The difference is to be meassured between the averages of groups and their performance on tasks ceteris paribus. IQ is supposed to predict anything thats G-loaded. Meaning that the reliability of IQ in perdicting g-loaded tasks increase as the sample size gets bigger Ceteris paribus. Maybe with dimishing returns.
Is this true PP?
In my view, IQ/G can be said to be anything that isn’t explained by environment on g loaded tests. Which includes self created environments like stress. Theres an “intrinsic to the subject(s) factor”.
No, thats not my view about G. I’m really tired…
😅😓🤤
Can you go into more detail about the product of the factor loading equaling the correlation?
It seems to me that if the wais had a lower g loading, then the SAT would have a high g loading to the point where it could exceed 1…. assuming the correlation stayed constant. What am I missing here
It seems to me that if the wais had a lower g loading, then the SAT would have a high g loading to the point where it could exceed 1
The logic only works if we assume that two tests only correlate because of their shared correlation with g, but if tests share non-g variance (i.e. verbal factor), it can overestimate g loadings to the point where you get absurdities like the one you describe.