“Wi-Fi connection logs in 23,391 students revealed that lecture attendance was about ten percentage points lower for classes at 08:00 compared with later start times.”
8am classes cost students about an hour of sleep and ten points of attendance, and more morning classes per week tracked with a lower GPA across 33,818 students. The researchers got there by mining Wi-Fi logs and LMS logins. Students woke up earlier than usual and never made the sleep back. The other finding is that your campus Wi-Fi knows whether you went to class.