I had no idea with my eldest. I had no idea with my second, until she was being tested and I could tell she was running out of questions in some sections and in another the tester said out loud "I've never seen that before".

Third child we won't test for at least a year and I am fascinated because I swing constantly between "she's at least as gifted... Definitely more gifted... who am I kidding she's not at all..."

Clearly im confused by my own kids, but I've pegged other people's kids within 5 points more than once...