American workers, on average, spend 45 hours a week at work, but describe 16 of those hours as “unproductive,” according to a study by Microsoft. America Online and Salary.com, in turn, determined that workers actually work a total of three days a week, wasting the other two. We actually work only about 1.5 hours a day. “The average full-time worker doesn’t even start doing real work until 11:00 a.m., and begins to wind down around 3:30 p.m.”

The experts disagree on how we are wasting all this time. The AOL survey says time is lost to surfing the Internet.

The Microsoft survey pointed to worthless meetings. Respondents said they spent 5.6 hours each week in meetings and 71 percent of them thought that those meetings “aren’t productive.”

Searching through messy desks is another diversion which makes us waste 1.5 hours a day.

The average professional workweek has expanded steadily over the last 10 years.There are those of us who work even when we are at home, driving or worse. A poll found that almost half of the small-business managers in the United States work during time meant for family, while 49 percent make business calls and check e-mail messages while behind the wheel; 18 percent read e-mail messages in the bathroom.

So how can we reconcile the conflicting trends — the fact that we are working harder and wasting more time?

“The longer you work, the less efficient you are,” said Bob Kustka, the founder of Fusion Factor, a productivity and time-management consulting firm in Norwell, Mass. He says workers are most efficient in concentrated bursts where they work hard on a few focused activities and then have a pause.

And this kind efficiency is receiving more attention. The new thinking is ‘if I know the job inside and out and I’m done faster than everyone else then why can’t I go home early?’ ”

A few companies are taking the concept of “watch what I produce, not how I produce it”. At the headquarters of Best Buy in Minneapolis, for