DD6 had 36 point growth in math this year on MAP. Some of that I attribute to her figuring out how to take the test but some of it was due to subject acceleration and actually learning more math. DD8 had 29, 22, and 20 points of growth for K, 1st, and 2nd without subject acceleration but I try to give her challenging work at home. Their reading growth was similar to your son's (ranging from 14 to 18 points and 2 to 3 times the "typical" growth).
Gifted children are capable of great growth but often times aren't getting the curriculum that's a match. If you look at the norms data, a 2nd grade child has to have at least 12 points of growth in math from the beginning of the school year to the end in order to stay at the 99% (205 to 217). That's significantly higher than the average growth and it would make sense that some of the high achievers will have growth a few standard deviations outside the norm.
http://pickens.it.schoolfusion.us/m...ssionid=14d1e9266e4482d198ebc39c6e6bc9c3Also look at page 78 for 2nd grade Math Growth Estimates and SDs. Starting at 205 gives an average of ~10 and a SD of ~5. The 27 points is between 3 to 4 SD's higher.
His growth is higher than "typical" but I wouldn't necessarily chalk it up to a mistake.
