[cma]

Still the ones who got in would be with more other students who opted in, the ones who didn't get in would be with more students who didn't opt-in to the lottery.

You would need to have a second group of those who lost the lottery and were all put into the same non-Montessori school with no others who didn't opt-in maybe.

[rahimnathwani]

Oh you mean it could all be peer group effects?

[cma]

Yeah but even then teachers that opt in to train in Montessori might just be better teachers, and converting a whole school system to Montessori, training everyone, might not have as good results.