I would definitely not doubt your child based on the Terra Nova. My oldest took the k, 1st and 2nd grade versions of that test about a decade ago and score consistently in the high nineties percentiles. I do remember that one year he only missed one or two questions out of almost 200 to hit the 99 percentile. Yet he was not more than MG and I can easily see a more intelligent child missing more questions from carelessness alone. The test is simply too basic to differentiate at the higher end. You need to go above level with something like SCAT with Johns Hopkinds or Explore to get a better read.
