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We measure intelligence using IQ tests but what does an IQ of 140 really mean in D&D terms? The easy answer is IQ/10 = INT*, but how accurate is it?
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140 is Genius level, IRL average is between 85 and 105 depending on which region you live in.
I never took offial tests but did the Karpov test and some other tests for myself, and i reached a score between 135 and 145. Some more modern IQ tests try to measure also social intelligence, but that gets a bit esoteric.
I consider myself to be above average, but surely not in the world top 1% or even top 5%, well maybe within the top 10-15%, that is my guess, but only with those older IQ tests which are based mostly on logic.
But intelligence also has an aspect of learned knowledge, not simply learned facts, but facts and how to implement and combine them.
IQ tests only can test common logic combination skills, and someone who is illiterate or does not know mathematics could still be quite intelligent, but would fail miserable at the test.
IRL IQ of 160+ is very rare, Einstein is rated to have probably had 165.
So your scaling is somewhat off (as is the common base for IQ tests eventually, who knows?), if we assume Int 20 aka IQ 200 people to exist