Ronald Wilson Reagan was an American politician and then became the 40th President of the Unites States from 1981 to 1989. He was an influential person because not only was he President for 8 years, but his Vice President became President for 4 years, and his Vice President’s son became President for another 8 years. This shocked the Democratic Party so much. In 2005, he was elected the Greatest American of all time.
So what was Ronald Reagan IQ?



Reagan was a great President because he changed the trajectory of America politics for decades. He also made America super powerful in the world.

People can argue whether his contribution was positive or negative, but anyone who changed the world as much as Reagan did seemed to have an IQ test of above 100.

In contrast, Reagan was the only American President who suffered from mental problem during old age. Therefore, Ronald Reagan IQ might be in the bottom 2.27% of US Presidents. This could be underestimate as some President have not lived to old age and also might be overestimate as Reagan seemed to be the only one to become impaired, even if there had been 88 Presidents.

If all facts above are correct and 44 US Presidents took an IQ test when they were old, Ronald Reagan IQ score would have been two standard deviations below the average US Presidents.

So the question here is how he would have scored at his peak?

In a research of Ian Deary and his team, they measured 101 people’s abilities through an IQ test when they were 11, and then tested them again by the age of 77 with the exact same test. After that, they found 0.63 correlation between the IQs tested at 11 and 66 years later.

So if Ronald Reagan IQ when he was old was two standard deviations below that of the average US President, his peak was likely 2 SD (0.63) = 1.26 SD below the peak of the average American Presidents. Moreover, US Presidents seemed to have peak IQs of approximately 130 with a restricted SD of 12.

Reagan’s likely peak IQ = -1.26 (12) + 130 = 115
As the standard error of the estimate is 9.32, you can be sure that Reagan’s peak IQ was anywhere from 96 to 134.


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