A lot of this is based on assumptions, but unless the study was somehow able to seperate "parenting" from pre-school attendence as an intervening variable, I don't necessarily think it's counter to his assertion.
I would argue that pre-school attendance could be a very strong indicator of parenting quality, if we can even try to quantify such a thing.
On the other hand, lack of pre-school could indicate a parent taking the pre-schooling responsibility upon themselves and providing a rather spectacular "home pre-school" environment.
I would argue that pre-school attendance could be a very strong indicator of parenting quality, if we can even try to quantify such a thing.
On the other hand, lack of pre-school could indicate a parent taking the pre-schooling responsibility upon themselves and providing a rather spectacular "home pre-school" environment.