Originally Posted by st pauli girl
Originally Posted by Kriston
As I have always heard it, siblings are usually within 10 IQ points of one another, barring some brain injury. That's the number I always hear thrown around. I have no source to cite though.

Anyone know where that "common knowledge" comes from?

I came across this on Hoagies, but I couldn't find the Silverman article anywhere:

8. If one child in the family is highly gifted, is it possible that the other children are gifted also?
Yes. Recent research indicated that in many cases siblings are within ten IQ points of each other (Silverman, 1987, November). If one child is highly gifted, it is quite possible that the other children are gifted, too. In many circumstances, it is beneficial for families to have all of the children evaluated.

Silverman, L K. (1987, November). Exploding the myth of the non-gifted sibling. Paper presented at the 34th Annual Convention of the Nationa1 Association for Gifted Children, New Orleans, LA.

http://www.hoagiesgifted.org/10_highly_gifted.htm

I say that DD3 is my ND child, but the other day, we sat down with a pre-k workbook, aimed at 4-5 yr olds, and she basically impressed me (read: shocked). While she is much older than DS5, when he did the same workbook pages, I am truly beginning to believe that she may also be GT. Plus, she is child #2, and it IS proven that child #2 doesn't generally develop (to the naked eye) as quickly as #1 b/c #1 is there to answer for #2 (especially when they are so close in age).

Anywho, without any tests done thus far, I would put DS5 in the moderate to highly gifted category with OE. And, if the above holds true, it would not surprise me to find that DD3 is not ND, but mild to moderate!