If anyone cares, it appears that PA GT students are smarter,

Here is a blurb based on 2004-2006 numbers (my last year report), that also includes 3rd grade...
English/Math/Reading/Science/Composite (talent kids norms)
3rd; 12.1/10.8/12.1/14.3/12.5
4th; 14.4/13.0/13.7/16.0/14.4
5th; 16.3/15.2/15.4/17.4/16.2
6th; 17.9/16.8/16.7/18.6/17.6
Weird, the average 8th grade scores are higher too, but I guess it fluctuates somewhat by year...
8th; 14.2/15.1/13.8/15.9/14.9
The 8th grade scores aren't dated, but the talent search ones are specific to PA and from 2004-2006.
Our report also has a nice breakdown that will give you talent search percentiles for each grade, for each specific subject score, which is nice.
It also breaks the scores down into 3 ranges, with the lowest range being a more "MG" range, and the two higher ones suggesting more radical needs.