Why Are We...? CLOZE #2

Target Language or Knowledge:

This puts students at a serious disadvantage. Numerous studies show that later start times are associated with lower rates of obesity, fewer car accidents and lower drop-out rates, as well as improved academic performance. In one study, shifting the start time from 7:20 to 8:40 a.m. significantly reduced depression as well. (Indeed, one has to wonder why we offer standardized tests like the SAT at 8:00 am; average scores would probably rise 15 points if we just switched to offering tests at noon.) A few districts have shifted start times successfully, so why hasn’t the practice been adopted more widely despite overwhelming scientific evidence?

a show are of accidents as performance the to depression has standardized 8:00 rise just at shifted why adopted scientific

What evidence does the speaker provide to support his claim?