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Atlas/Presidents/John Quincy Adams
Official measure

John Quincy Adams’s IQ

John Quincy Adams served as the 6th president of the United States (1825–1829). Simonton 2006 Table 1 column II-C (2C) estimates 175; that is a historiometric model, not an administered IQ test.

Direct answer175

Simonton 2006 2C estimate: 175. Historiometric model, not a measured IQ score.

See 175 on the IQ scale
1767–1848
Evidence ledger

What the record supports

Every card keeps the measure, year, method, and limitations attached to the number—or explains why no number is shown.

Historical estimate2006
175estimated IQ points

Simonton 2006 Table 1 II-C (2C) estimate

Table 1 column II-C is 175 (displayed as 175). II-C is the ages 18–26 estimate corrected for data reliability. Simonton also reports I-U, I-C, and II-U; those other variants are lower or equal. 2C is still a model, not a test.

Simonton 2006 2C estimate: 175. Historiometric model, not a measured IQ score.
Method and limits

Simonton used expectation-maximization with prior biographical ratings of intellectual brilliance, openness, and the limited Cox retrospective estimates. This atlas ranks and displays column II-C.

  • No administered IQ test underlies this record.
  • The models depend on historical biographical ratings and assumptions about missing values.
  • Displaying 2C as one number is a ranking convention, not proof of a test result.
  • II-C is the most generous of the four variants; the lower variants would produce a lower or equal estimate.

Uncertainty: 2C is one of four published model variants, not a confidence interval or an administered test score.

Full evidence investigations
Evidence trail

Why this page exists

John Quincy Adams is a high-demand presidential IQ search. The first useful answer is the published 2C integer (175), then the method that produced it, then what it is not.

  1. Adams is 175. John Quincy Adams’s II-C value is 175.0—the maximum in Table 1. The other three variants still sit between 165 and 170.
  2. The next rung is 160. Thomas Jefferson and James Madison are 160.0 on II-C. John F. Kennedy is 159.8, displayed as 160. Bill Clinton is 159.
  3. The low end is still an estimate. Ulysses S. Grant is 130 on II-C, the lowest of the 42. George W. Bush is 138.5, displayed as 139. None of these is a classroom IQ.

Conclusion. On Simonton 2006 Table 1 II-C, John Quincy Adams is highest at 175. Jefferson and Madison are 160. Obama, Biden, and Trump are not in that table.

Where 175 sits on the IQ scale

This is the same mean-100, SD-15 model used on the homepage. It explains the integer. It does not turn 2C into a WAIS result.

Explore IQ 175 on the interactive bell curve · Presidents sorted highest to lowest.

Questions this page answers

What was Adams's IQ?
This atlas displays 175 from Simonton 2006 Table 1 column II-C (2C). It is a historiometric estimate, not an administered IQ test.
Is that a real IQ test?
No. Simonton reconstructed estimates from biographical ratings and earlier Cox-style figures. There is no public WAIS or Stanford–Binet protocol for this number.
Why show one number instead of a range?
The paper publishes four variants. IQ Caddy ranks and displays II-C so the list can be sorted highest to lowest, with the Estimate badge attached.

Related investigation: Who has the highest presidential IQ on Simonton 2C?.