Do you think your DD needs the GT magnet? How is she doing in school? How does she like it? Do you feel she’s adequately challenged? What do they provide for GT kids outside of the magnet? And what are the cutoffs for the magnet?
Sometimes the GT magnets are there to serve kids who otherwise aren’t being served in the regular schools. For example, some magnets will increase the pace of instruction and provide accelerated materials because HG kids don’t need all the repetition. I don’t have any facts about your particular situation, but I think it’s very important to look at what you think your DD needs for school and then try to match up with available programs. It’s possible the magnet isn’t quite right for your school. Then again, it’s possible that her scores aren’t reflecting what you see too.
