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?
Oh, and in realizing that I didn't really say anything about this, no, I don't think that they are comparable. The WISC and the SB-LM use different methods for calculating IQ. The LM used a ratio IQ whereas modern tests use a deviation IQ.
Essentially, a ratio IQ was mental age divided by chronological age whereas deviation IQ looks at how much one deviates from the norm or where one falls on the bell curve. It tells you more how one compares to his age peers and is just a totally different way of figuring IQ. See this explanation:
http://www.iqcomparisonsite.com/IQBasics.aspx
