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Commenter “Another William Playfair Web” asked me to estimate the IQ of Donald Trump’s chief spokesperson Katrina Pierson, and was especially interested in predicting it from her worldly success, as I had done with other luminaries.

As the fiercely articulate face of Donald Trump, a man who has revolutionized American politics and is the Republican front-runner for President, Pierson has suddenly leapfrogged over the competition to become, arguably, the most powerful black conservative in America.  All this from a woman who is not yet 40!

So what is her IQ?

I estimate there are about 31 million American adults who would be socially classified as black, and it seems about 10% are Republicans (assuming those who don’t vote would have the same politics as those who do).  Thus Pierson is the most powerful out of 3.1 million black adult conservatives, giving her a normalized Z of +5 when it comes to power.

Assuming the correlation between IQ and power is about 0.4 (and I base that on the fact that U.S. Presidents seem no more than 40% as extreme in IQ as America’s smartest adult) then we’d expect Pierson’s Z score for IQ to be only 40% as high as her Z score for power:

Pierson zIQ = +5(0.4)

Pierson zIQ = +2

Thus we’d expect Pierson’s IQ to be 2 standard deviations above the black conservative IQ mean.

Let’s assume black conservatives have a mean IQ of 78 (U.S. white norms) with a standard deviation of 15,   The true standard deviation is probably a bit lower than 15, but given that distributions, even for deviation IQs, tend to have fat tails, it’s best to err on the high side.

Thus Pierson’s expected IQ would be 2(15) + 78 = 108

White ancestry

Because Pierson has light skin and Caucasoid features, we might very crudely guess she’s about 75% white.  Her mother is white, and I suspect her black father was largely white too.  According to scholar Richard Lynn, “blacks” who are almost all white, have IQs 10 points higher than the average African American (who is almost all black).

Thus, we could very crudely add 10 points to Pierson’s expected IQ, bringing her to 118 (U.S. white norms), or roughly 120.

Idea Density

Commenter “Another William Playfair Web” also wanted to estimate Pierson’s IQ from “Idea Density” (ID) as I had done with Oprah.  “Idea Density” has never, to my knowledge, been formally correlated with IQ but is seen as a measure of overall neurological and cognitive functioning.  I have used the concept only sparingly, because my sense is that it only strongly predicts intelligence under very controlled standardized conditions (such as the famous nun study).

One such standardized controlled set of conditions occurred when asked a sample of the most powerful women in business to submit to a Q&A, most of whom responded by email.  It turns out that Pierson also participated in a similar Q&A for a different publication.  I copied and pasted Pierson’s answers, ran them through a computer (with bracketed fill-in words provided by the editor removed and multi-word names replaced with place holders) and found she clocked in 0.525, which using the age adjusted norms for the powerful business women, equated to an IQ of 120.

It was nice to see this independent method confirm the very crude statistical prediction made above, from her status as the most powerful black conservative, but given that Pierson was not answering the same questions as the reference group from, and given that she answered by speech, and most of them answered by email, this score should be treated with great caution.

An IQ of 120 is very high, making Pierson smarter than 90% of white America.  It’s worth noting that the average SAT (reading + math) at her alma mater (the University of Texas at Dallas) is an impressive 1261, which according to my formula, equates to an IQ of 126 (U.S. norms) which is 124 (U.S. white norms).  Because of possible affirmative action, I’d expect black students there to average well below this on the SAT.  On the other hand, Pierson not only attended, but she graduated, and with a degree in STEM (even I don’t have a STEM degree :-)) so this likely cancels out any affirmative action edge.

Based on how fluently Pierson defends her boss from tough questioning in the media, it is tempting to think her IQ might be 130 or even 140, but we must remember that there’s a big difference between a great talker and a brilliant mind.  But at the very least, Pierson is very bright and great at her job.  Let’s watch her in action: