Sunday, February 2, 2014

When the sum of many individually significant effects becomes frivolous

There is an odd divide here. Ask why one person had an unproductive day at work, and lack of sleep often seems an obvious answer. But ask why national productivity has fallen, and reduced sleep can appear to be a frivolous answer. Yet what is total output but the sum of all individuals’ work? ...

One careful study found that the number of “short sleepers” — those who got fewer than six hours of sleep a night — rose 22 percent from 1975 to 2006, a trend that was most pronounced and significant among full-time workers.