[xoxoxoBruce]

They're making a big mistake.

That output does not rise or fall in direct proportion to the number of hours worked is a lesson that seemingly has to be relearned each generation. In 1848, the English parliament passed the ten-hours law and total output per-worker, per-day increased. In the 1890s employers experimented widely with the eight hour day and repeatedly found that total output per-worker increased. In the first decades of the 20th century, Frederick W. Taylor, the originator of “scientific management” prescribed reduced work times and attained remarkable increases in per-worker output.

One is that increasing a team’s hours in the office by 50 percent (from 40 to 60 hours) does not result in 50 percent more output (as Henry Ford could have told them). Most modern-day managers assume there will be a direct one-to-one correlation between extra hours and extra output, but they’re almost always wrong about this. In fact, the numbers may typically be something closer to 25-30 percent more work in 50 percent more time.

After WWII, as the GI Bill sent more workers into white-collar jobs, employers at first assumed that the limits that applied to industrial workers probably didn’t apply to knowledge workers. Everybody knew that eight hours a day was pretty much the limit for a guy swinging a hammer or a shovel; but those grey-flannel guys are just sitting at desks. We’re paying them more; shouldn’t we be able to ask more of them?

The short answer is: no. In fact, research shows that knowledge workers actually have fewer good hours in a day than manual laborers do — on average, about six hours, as opposed to eight. It sounds strange, but if you’re a knowledge worker, the truth of this may become clear if you think about your own typical work day. Odds are good that you probably turn out five or six good, productive hours of hard mental work; and then spend the other two or three hours on the job in meetings, answering e-mail, making phone calls and so on. You can stay longer if your boss asks; but after six hours, all he’s really got left is a butt in a chair. Your brain has already clocked out and gone home.