Scenario A: Start-time pilot and student outcomesA district…

Scenario A: Start-time pilot and student outcomesA district piloted a later start time at one high school for one grading period. Central shifted from 7:20 AM to 8:05 AM. North stayed at 7:20 AM. Central also launched a new after-school tutoring program during the same period; North did not. Data (averages): Central before: sleep 6.4 h; tardies 18 per 100; exam 78% Central after: sleep 7.1 h; tardies 11 per 100; exam 80% North before: sleep 6.5 h; tardies 17 per 100; exam 79% North after: sleep 6.6 h; tardies 16 per 100; exam 79%A4. Which conclusion is most defensible?