LinCO-
She based the diagnosis of ADHD on several things....first was the BASC screening forms that his teacher, my husband and I filled out. Second, she administered a computerized test (can't remember the name right now) that tests for inability to control impulse. Third, she was able to observe his behavior during the testing and interviews. I feel very confident that the diagnosis is correct. It shows not only in his classroom performance, but also his ability to follow through on instructions at home or to pay attention while playing extracurricular sports like baseball or soccer.
She diagnosed him with a disorder of written expression based ont the fact that his WIAT score in writing was more than 15 points below his FSIQ and by having him do writing samples during his testing. He writes some big letters, some little, has lots of reversals, does not use punctuation, has tons of mispellings (although he aces every spelling test and won his class spelling bee).
Does this help answer the question? I'd love any advice or input!