1. Are the Wisc IV extended norms scores comparable to SBLM scores because both go up to 200+? A tester who is quite respected in my area advised me against testing my son on the SBLM because she said it will not differ much from the Ex. Norms on the Wisc IV. I am not doubting her exactly, just wondering how this is possible when both tests are not equal?

I'm a fan of testing to open doors. If a child tests 143, and needs 145 for a program that you absolutely feel he would benefit from, by all means test again. But if the kid scores 146, I'd move on. It really does become more about what the child continues to do in time, than some number on some day.

Solaris, in reading back, I see your kid did make DYS cuts on the WISC-IV.

Yes, that's exactly it. Kids with the same IQ scores are going to have different needs in reality. Whether the 145 kid who needs more educationally and otherwise than another 145 kid actually has a higher IQ, maybe, but it probably doesn't matter. There are few, if any programs, that have a cut above 145 or so. If a child hits that point, the doors are open and it is then up to the child, time, and whatever other factors come into play to figure out what more needs to be done for that child.

Since 1979, Silverman's testing facility and practice, the Gifted Development Center, has given nine hundred and eleven children I.Q. scores of 160 or above, including sixty-four in the 200s. Unless almost every young genius in the country is coming through her office, then, she is recording a far higher incidence of profoundly gifted children than the statistical distribution of I.Q. results should allow. The particular I.Q. test that Silverman, almost alone among her peers, relies on may have something to do with this. Although she begins each assessment with one of the more widely employed I.Q. tests, when a child scores extremely high Silverman goes to the Stanford-Binet Intelligence Scale, Form L-M.
The Stanford-Binet was first developed in 1916, and enjoyed the status of the most widely accepted I.Q. test through three iterations, up to and including the Form L-M. The Form L-M (after the first names of its authors, Lewis Terman and Maud Merrill) came out in 1960, was updated in 1972, and then was replaced in 1986, by the Stanford-Binet Intelligence Scale, Fourth Edition. The update was never well liked by psychometricians, and several more recently developed tests, such as the Stanford-Binet Fifth Edition and the current Woodcock-Johnson exam, are considered more comprehensive and reliable. Silverman uses the Form L-M because it's the only version that officially calculates scores above 160. "There's nothing else to use with kids this gifted," she told me. But some critics of the test say that it not only assesses higher scores; it tends to produce them. "The Form L-M uses children from several decades ago as its comparison group, so of course the scores are going to skew much higher if it's used on today's kids--every generation of children is more academically and environmentally advanced than the previous generation," Susan Assouline, the associate dean of the gifted-education program at the University of Iowa, said. "It's not a useful test in this day and age."

I found this excerpt from Konigsberg's 2006 New Yorker piece pretty compelling