There’s reason to believe that a seven-day week with a two-day weekend is an inefficient technology: a growing body of research and corporate case studies suggests that a transition to a shorter workweek would lead to increased productivity, improved health, and higher employee-retention rates.

The five-day workweek might be limiting productivity. A study in the American Journal of Epidemiology found that those who worked 55 hours per week performed more poorly on some mental tasks than those who worked 40 hours per week. And Tony Schwartz, the author of Be Excellent at Anything, told Harvard Business Review that people work best in intense 90-minute bursts followed by periods of recovery. Taken together, these findings suggest that with the right scheduling of bursts and rests, workers could get a similar amount of work done over a shorter period of time.

Moreover, there’s some anecdotal evidence that a four-day workweek might increase productivity. Google’s Larry Page has praised the idea, even if he hasn’t implemented it. And Jason Fried, the CEO of Basecamp, has his employees work four-day, 32-hour weeks for half of the year. “When you have a compressed workweek, you tend to focus on what’s important.  Constraining time encourages quality time, ” he wrote an op-ed in The New York Times. “Better work gets done in four days than in five,” he concluded.

Work less. And smarter.