First, I believe this is not a once-size-fits-all question. Communities in different areas tend to work around schedules that are best for most people that live there. I have moved around the country a few times and I can assure you that where I live now, people tend to start and end their day earlier than people tended to where I lived last. It sucks, but I had to adapt. School times need to be set in accord with locality needs and preferences. Secondly, circadian rhythms were cited as a factor but there is one full hour difference in solar time for folks living at opposite ends of the same time zone. Again community locality within a time zone is the overriding factor for circadian rhythm concerns and not the actual ‘clock’ time. So, I do not believe the proposed studies would be of much value.