mom2sofia-- because my DS8 has ADHD and a language impairment, he has taken many tests. IQ, achievement, language, ADHD specific tests for working memory, and of course, school standardized.
The test scores with the least variability are the IQ tests-- and even then, some variability in the subtest scores on a level similar to your DD's scores.
I will second aeh on math- my DS was an early, avid little mathematician. His first WJIII achievement in math were *extreme.* A year later, he took the WJ IV-- he was older, age mates were now learning more math, different testing norms, etc. He still did great, but not so extreme.
Now, DS gaining a second wind on math and is ready to move out of elementary aged math (he's eight)-- I suspect if we tested him in six months, he would be back on the extreme score with what he is learning now. In two years, his score may go down again as some age mates gain ground.
