Presidents Ranked by IQ: The Real Study, and the Hoax Everyone Still Quotes

Search us presidents ranked by iq and you will find a tidy list, usually with Bill Clinton near 182 and George W. Bush at 91. That list came from a chain email in 2001, and the institute it credits has never existed. There is a real academic study — but it says something quite different, and the most interesting thing in it is not the ranking at all.

Did Any President Take an IQ Test?

No. Not one has ever released a professionally administered score, and most of them served long before intelligence testing existed at all. The first test for children appeared in 1905; the first widely used adult test, the Army Alpha, in 1917. By then 27 men had already held the office.

So every presidential IQ number you have ever seen — every single one, in every ranking — is a reconstruction. The only question worth asking is who reconstructed it, and whether they showed their work.

The 2001 Hoax That Still Poisons Every Ranking

In July 2001, months after George W. Bush’s inauguration, an email began circulating. It reported a four-month study by the Lovenstein Institute of Scranton, Pennsylvania, which had supposedly analysed presidential speeches and scored every president since Franklin Roosevelt. Clinton came out at 182. Bush came out at 91.

There is no Lovenstein Institute in Scranton, or anywhere else. The researchers quoted in the article do not exist. The publication it cited, the Pennsylvania Court Observer, does not exist either. Snopes debunked the whole thing on 18 July 2001, within weeks of it appearing. Later that year the pranksters registered a domain and built a fake institute website to keep it going.

The invention was politically motivated, and the giveaway is in the maths. The hoax gave Democratic presidents an average of 156. On a standard scale that would place the average Democratic president in roughly the top hundredth of one percent of the population. Nobody’s party affiliation produces that.

The Real Study, and How It Worked

The genuine research is Dean Keith Simonton’s 2006 paper in Political Psychology, titled “Presidential IQ, Openness, Intellectual Brilliance, and Leadership.” Simonton is a psychologist at UC Davis and has spent decades on historiometry — the statistical study of historical figures.

He did not test anyone. He combined three existing sets of assessments:

• Cox’s 1926 IQ estimates, which existed for only 8 presidents.
• Intellectual Brilliance, a factor score built from biographical profiles rated on 300 descriptors, available for 39 presidents.
• Openness to Experience, from expert personality ratings, available for 32 presidents.

Those three measures correlate strongly with each other despite coming from completely different methods, which is what let him use a statistical technique called expectation-maximisation to fill in every gap and produce a complete set of figures for all 42 presidents.

Each president ended up with four IQ estimates, not one. Cox had calculated scores for two age windows — birth to 17, and 18 to 26 — and each of those came in an uncorrected form and a form corrected for how patchy the surviving biographical record was. Hence four numbers: I-U, I-C, II-U, II-C.

Only 8 of the 42 Numbers Are Really Theirs

This is the detail that reframes the entire ranking, and almost nobody mentions it.

Cox’s original 1926 work covered only eight presidents: Washington, John Adams, Jefferson, Madison, John Quincy Adams, Jackson, Lincoln and Grant. Those eight have IQ figures derived from their own childhood records.

The other 34 presidents have no IQ estimate of their own at all. Their numbers were computed by the algorithm from their Intellectual Brilliance and Openness scores. Simonton is completely transparent about this — the imputed values are printed in a different typeface in his table, and he writes that “the IQ scores must therefore be considered more tentative and approximate than the other two scores.”

So when a listicle tells you John F. Kennedy’s IQ was 159.8, that number was never an assessment of Kennedy’s intellect. It is what the model predicts, given how historians rated his curiosity and breadth of interest. The same goes for Clinton, for both Bushes, for Reagan, for every twentieth-century president.

In the table below, the eight rows with original Cox scores are shaded and tagged, so you can see exactly which numbers rest on the person and which rest on the model.

Every President, All Four Estimates

Transcribed from Table 1 of the 2006 paper and checked against the column averages Simonton reports separately. Higher is not necessarily more accurate — the four columns are four different methods, not four attempts at the same thing.

I-U ages 0–17, uncorrected · I-C ages 0–17, corrected for data reliability · II-U ages 18–26, uncorrected · II-C ages 18–26, corrected. Shaded rows tagged Cox are the eight presidents with original 1926 scores; the other 34 are statistically imputed. Intellectual Brilliance is a z-score, where 0 is the presidential average and 1.0 is one standard deviation above it. Cox’s figures use a standard deviation of 16, not the 15 used by modern tests.

Highest and Lowest IQ Presidents

The highest IQ president by these estimates is John Quincy Adams; the lowest IQ president is Ulysses S. Grant. On the most-quoted column, II-C, the top of the list runs: John Quincy Adams 175, Jefferson 160, Madison 160, Kennedy 159.8, Clinton 159, Carter 156.8, Wilson 155.2, John Adams 155, Theodore Roosevelt 153, Garfield and Arthur 152.3, Lincoln 150.

The bottom: Grant 130, George W. Bush 138.5, Monroe 138.6, Taft 139.5, Buchanan 139.6, Harding 139.9.

Two things are worth noticing. First, the John Quincy Adams IQ figure is one of only eight drawn from a real Cox score, so his position at the top is better grounded than most of the list. Second, the gaps are small relative to the uncertainty. Kennedy at 159.8 and Clinton at 159 differ by less than a point, on estimates that Simonton himself calls tentative. Ranking them against each other is not meaningful.

Note also that Grant, the lowest in the study, won the Civil War. John Quincy Adams, the highest, served a single term and was voted out.

Obama, Trump and Biden Aren’t In It

The study was published in 2006 and ends at George W. Bush. Barack Obama, Donald Trump and Joe Biden were never assessed, because the data simply did not exist when the work was done.

This matters because charts from Simonton’s study circulate on social media with modern presidents added. The most common version claims a figure of 156 for Donald Trump. Snopes examined that image and found the chart genuine and the added number fabricated. Simonton himself told the Washington Post that nobody has conducted another study extending the analysis to recent presidents.

So if you see a ranking that includes any president after 2009 with a specific number attached, that number was invented by whoever made the graphic.

What Simonton Actually Found

Here is the part that gets skipped every time, and it is the most useful finding in the paper.

Simonton correlated all six of his measures against a composite of presidential performance drawn from twelve separate expert surveys of historians and political scientists. The IQ estimates barely moved the needle.

The four IQ estimates each explain about a tenth of the variation in how historians rate a presidency. Intellectual Brilliance explains three times as much, and when Simonton runs a regression including years in office, war years, assassination, scandals and war-hero status, it is the only intellect measure that stays statistically significant.

Intellectual Brilliance is built from descriptors like curious, wide interests, insightful, inventive, sophisticated. It is closer to intellectual engagement than to raw processing power. The finding, in plain terms: how interested a president is in ideas predicts their standing with historians far better than how high their estimated IQ is.

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Last updated: August 2026