Your Explore Score Report should include norm data which compares how your child scored to the 8th graders who took the test in the Fall of 2013.
I was surprised with my DS's Reading score this year too - he scored 2 points lower than last year compared to his English score which went up 5 points.
If you can afford to IQ test, that might be the quickest and easiest. I don't know the rules on the timing of the brief vs. full test, but maybe you could have her tested with one of the other tests. I also think her scores are very strong so you may have luck with the portfolio. Here's a link to a thread with info about portfolio. Good luck!
http://giftedissues.davidsongifted....6805/Achievement_Test_and_Portfolio.html
