Which US president had the highest reported IQ score?
Executive summary
The most widely cited scholarly estimate places John Quincy Adams as the U.S. president with the highest reported IQ, with Simonton-era figures typically in the mid-160s to mid-170s (commonly reported as ~168–175) [1] [2]. That conclusion rests on historiometric estimates—not on direct, standardized IQ testing of presidents—and different compilations and methodologies produce somewhat different top-ranked names and scores [3] [4].
1. The headline: John Quincy Adams often tops IQ lists
Multiple popular and academic compilations identify John Quincy Adams as the president with the highest estimated IQ—Reader’s Digest cites Adams at 175 (a common citation on aggregator lists) while other sites using Simonton-derived numbers put him around 168–169, making him the highest-scoring name that repeatedly appears across lists [1] [2].
2. Where those numbers come from: Simonton’s historiometric estimates
The single scholarly source most commonly behind presidential IQ rankings is Dean Keith Simonton’s historiometric study, which estimated IQ-like scores for presidents using biographical evidence and correlates of intelligence rather than direct testing, and these estimated values are what many websites and articles reproduce [3] [4].
3. Why the figures are estimates, not measured IQs
No reliable public record exists of standardized IQ tests administered to most presidents, so figures presented in media roundups are extrapolations; Simonton’s method infers IQ-related traits from writings, accomplishments, and historical records and then translates those into an estimated IQ metric, a process scholars caution is an imperfect proxy for actual test scores [4] [3].
4. The variation problem: different lists, different tops
Various compilations and popular rankings diverge: some list Thomas Jefferson, James Madison, Abraham Lincoln, John F. Kennedy or Bill Clinton near the top depending on which version of Simonton’s corrections or which aggregator’s averaging method is used, and some non-academic lists inflate precision or add numbers from other sources, so the “highest” president can shift by list [2] [5] [6].
5. What the numbers actually mean for leadership and policy
Scholars urge caution in equating a single IQ estimate with presidential effectiveness: peer-reviewed analysis shows Simonton’s IQ-like metric is only one of several psychological measures (e.g., “Intellectual Brilliance,” Openness) and that raw IQ estimates have limited predictive power for presidential performance compared with broader personality and contextual factors [4].
6. The balanced answer: highest reported—by estimate—John Quincy Adams
Given the available reporting and the prominence of Simonton’s historiometric work in modern compilations, the straightforward answer is that John Quincy Adams is most frequently reported as having the highest estimated IQ among U.S. presidents (commonly cited in the ~165–175 range) but that this is a derived estimate, subject to methodological debate and variation among secondary lists [1] [2] [4].
7. Caveats and transparency about sources and agendas
Popular lists (Reader’s Digest, Ranker and others) amplify Simonton’s numbers for click-driven comparisons and often omit methodological nuance, while academic write-ups highlight limits and alternative metrics—readers should treat headline IQ rankings as interesting historical curiosities rather than definitive measures of presidential ability [1] [5] [4].