Also the fact that IQ is a very relative scale. IQ = 100 is defined as the median IQ, and as the median moves the meaning of IQ = 100 is redefined. 15 points

Also the fact that IQ is a very relative scale. IQ = 100 is defined as the median IQ, and as the median moves the meaning of IQ = 100 is redefined. 15 points of IQ is defined as 1 sd. And again, as variance changes, the equivalence of IQ points changes as well.