138.9–159.8estimated IQ points
Simonton 2006 historiometric presidential IQ estimates
The minimum and maximum of four estimates (I-U, I-C, II-U, and II-C) reported in Simonton's Table 1.
Published historiometric estimate, 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.
- No administered IQ test underlies this record.
- The models depend on historical biographical ratings and assumptions about missing values.
- The four variants should not be collapsed into a definitive score or ranking.
Uncertainty: This min–max span summarizes four model variants; it is not a confidence interval or test-score range.