I'm not familiar with TerraNova itself, but it is an achievement test that is designed to measure how much of grade level material the child knows. We tend to think that any child should do better on easy tests than hard tests, but HG kids sometimes do worse with tests that are easy because the easy questions confuse them. My DH calls this 'overthinking' the test. There is also the problem that easy questions are boring and hard to consentrate on. I think that the fact that the numbers are in the top 10% mean that the 6th grade work is certianly not too hard for your child. That is pretty much all you can see from this sort of test with a gifted child. You can't say he is properly challenged because 93% is so far away from 100%. It is possible.
You might want to talk to the school and see if they allow him to take the TerraNova for 7th grade and 8th grade. Once you have those data points you can draw some reasonable conclusions.
I get this from reading about the theory behind giving children 'above level tests' and working backwards.
Smiles,
Grinity
