Method (1) seems like it could provide some valid insight. To me, however, collecting information from a number of schools seems like the best approach. I'm no

Method (1) seems like it could provide some valid insight. To me, however, collecting information from a number of schools seems like the best approach. I'm not terribly familiar with how studies are done in schools. Is it incredibly difficult to collect cross-section which is large enough to control for differences in teachers/students? Maybe my inner economics student is showing through, but this seems like a prime target for good old-fashioned regression analysis.