[waster]

There are actually specific terms to label intelligence based on the number of standard deviations from the norm (100 IQ). Two to 3 SD's is highly gifted; 4-5 is exceptionally gifted; and 6+ SD's is profoundly gifted. The numbers change depending on what IQ instrument is used, but the terms for those SD brackets remain the same. I forget what Mensa's IQ threshold is and what IQ instruments they accept as measures (I was a Mensa member for a year about 10 years ago, but they took my only available score, a GRE score, as proof), but it's possible that "exceptionally smart" is technically correct, based on SD thresholds.

[ben_w]

Just to add, by definition 6σ is one in a billion. It isn’t just “profoundly gifted”, but rather “there are seven of you”.

[barry-cotter]

IQ is a fat tailed distribution. There are way more people in the tails than the test’s definition and morning would suggest.

[ben_w]

IQ is defined to be a normal distribution. Intelligence, on the other hand, isn’t.

This is one of the problems with IQ as a measure of intelligence. IQ 150 doesn’t mean doing mental arithmetic faster than IQ 100 by the same margin that IQ 100 beats IQ 50, only that IQ>150 is as rare as IQ<50.