"If less sleep leads to a drop in attention in class, children may miss out on learning and chances to be creative. If they are easily irritated and frustrated because their bodies and brains are tired, they may not learn as much either."-Reut Gruber.
Teachers were asked to observe their students behavior, some were asked to lose an hour of sleep, others were asked to gain one hour of sleep. The results were different.
Starting school later in the morning will improve student performance in school because students will be more alert and able to earn better grades. Starting school at 8:30 is too early.