Good afternoon. I am Elena, and I looked at what happened when our district moved the high school start time from seven forty to eight thirty.

The research behind the change is about biology, not discipline. During adolescence, the body's sleep timing shifts later by about two hours, so a teenager told to fall asleep at nine is being asked to sleep before the body is ready.

Two years after the change, our district reported that first period absences fell by nearly a third, and the number of students arriving late dropped as well.

I want to be careful here. Those are attendance numbers, not test scores, and the district changed two other things in the same year. Whether grades improved because of the start time is a question nobody has answered yet.

So the clearest result is also the least dramatic one. More students are in the room when the day begins.