Scored above the total ceiling score of IQ 164+ sd16 (160+ sd15) on WISC-R at age 7 and one month,
a result that by her own account the Psychologist who tested me
had never seen in practice in 20+ years of her career by that time.
However, I refused skipping any grades,
even though I was told that theoretically I should skip more than four.
Since then, I have taken five more professional standardized
tests, scoring between IQ 163 sd16 (per recent 1994 norms for the CFIT-3a; old 1960's norms list 161 sd16 for the same raw score) and IQ 170 sd16 on them.
Since these are all at the very end level of meaningful statistical measurement they indicate a value above these numbers. One way of trying to get around this ceiling limitation would be applying the method of variance of sums on these scores which leads to an indicated total rarity IQ of 171-173 sd16. However, this method is limited too and basically, beyond the range of about 160-165 sd16 there is virtually no sufficiently substantial way (other than estimations through ratio scores and variance of sums) to establish what a person's true level of cognitive ability is (see: Spearman's Law of Diminishing Returns).
In a 1993 book "Exceptionally Gifted Children", Miraca Gross reports cases of subjects scoring at or near the ceiling of the WISC-R who, when tested with the higher ceiling Stanford-Binet L-M, achieved ratio scores of 198 and 200 which translate to regular deviation values of 172-174 sd16, same as the variance of sums of the combined deviation scores I achieved.