The bottom line is that the people actually working in real classrooms with real students have always done this, WILL always do it, and pretty much cannot serve ANY students well unless they do it, and they don't need a lot of data on "best practices" and "inclusion" to know how to do the right things with the construct.
I have to disagree HK. I'm sure that thoughtful teachers group by ability, but I've met too many people who are offended by the idea to believe that everyone who works in a classroom groups by ability. DS12's second grade teacher had him tutor the other kids when the work was too easy for him; when I complained after he told me, she told me that she'd "been taught to use her best students." Another one told me, in a panel discussion where I was the odd man out, that advancing the better students wasn't necessary because "they were already proficient [in the task at hand]!!!" The idea that they could move to the next task seemed alien to these people. Etc. Isn't lockstep teaching one of the things that drives many of us to this site?
It's an ideology thing. Randi Weingarten wouldn't be where she is today if her ideology represented a small minority.
