I’ve always been curious about people who got advanced degrees from elite universities, like Harvard law school graduates for example, because not only do they have the most advanced degrees, but from the most prestigious schools to boot. We know Harvard undergrads average IQs around 17 points higher than the average university undergrad (125 vs 108 (white norms); the difference is much larger on the SAT because it’s used to select Harvard undergrads, thus causing a selection bias.
We also know law school grads average about 11 points higher than the typical university grad (119 vs 108 (white norms)).
A naive reader might think that if Harvard undergrads are 17 points smarter than the average university grad, and if law grads are 11 points smarter than the average university grad, then Harvard law grads must be 17 + 11 = 28 IQ points smarter than the average university grad, giving them an IQ of:
108 + 28 = 136
But this would only be true if Harvard students and law grads were independent groups. In reality, being a Harvard undergrad dramatically increases your odds of getting a Harvard law degree (or equivalent).
Law degrees (i.e Juris Doctor degree) are now classified as a type of doctor’s degree and Harvard confers about 1,455 such degrees a year. Given that U.S. citizens are about 78.9% of Harvard, we can guestimate U.S. citizens recieve only 78.9% of their doctor’s degrees, so roughly 1,148.
Given that about 4 million Americans come of age every year, we can say getting a Harvard Doctor’s degree is a one in 3,484 achievement, and thus the median such person would be a one in 6,969 achiever.
If there were a perfect correlation between IQ and academic success, this would imply an IQ of 154 (U.S. norms) but since the correlation between IQ and highest degree attained is only about 0.55 an IQ of 0.55(54) + 100 = 130 is expected.
Converting to white norms gives an IQ of 128.