The results from analyzing the number of work days per week on efficiency were mixed. In two studies, there were differences of about 7 percent (absolute) in the 6- and 7-day workweeks. In two other studies, there were no differences or they showed the 6- and 7-day schedules to be slightly more efficient than the 5-day schedule. For one study, the results were erratic. (SD-60, p. 34)