DS skipped first grade but the school is the one who suggested it. At the time he was at private parochial school and I was very surprised when they came to me a few weeks into first grade and suggested the move to second. I was not surprised at his ability but shocked that the school was the one making the first move. The public schools would never have done that even with the tests.
You are right that private testing is not cheap but if you suspect some high scores I think it is worth it. My only regret is that I did not research to find someone experienced with gifted kids.
