I think the group tests are crummy. I think they overID some kids and miss others. And we're also in a school system that IDs roughly 30% of kids as GT in one area or another. Some of that is probably accurate because of who lives here: corporate executives, professors, etc. Even so, I think that percentage is too high.
But I also know from personal experience that I tend to assume that MG kids are ND kids. We were in a toddler playgroup with several MG kids--who I now truly believe are MG!--and they seemed pretty "slow" to me back then in comparison to DS, who I thought was MG to HG.
I guess I'm suggesting that it may well be a combination of factors. But don't disregard your own potential to underestimate your DD. That's just personal anecdote talking, but I still think it is relevant and important.
