I have found MAPS quite helpful in advocating for my child within the school system. Because it allows the kids to test out of level it gives over time, a fairly accurate view. Two caveats: The grain of salt issue is definitely still there. My dd10 scored off the scale in reading this fall. In no way do I feel that she really has the schema or sophistication of a 12th grade AP student! Second, and apparently fairly common with gifties, the growth model isn't consistent. For example, her math and language scores went down last year about 10 points, then up 15 and 20 respectively.