Have we really hada huge productivity spurt in this country recently -- or are people just being worked a lot harder. In a New York Times op-ed piece, Stephen Roach of Morgan Stanley makes a good case for the latter interpretation:

...productivity measurement is more art than science — especially in America's vast services sector, which employs fully 80 percent of the nation's private work force, according to the United States Bureau of Labor Statistics. Productivity is calculated as the ratio of output per unit of work time. How do we measure value added in the amorphous services sector?

Very poorly, is the answer. The numerator of the productivity equation, output, is hopelessly vague for services. For many years, government statisticians have used worker compensation to approximate output in many service industries, which makes little or no intuitive sense. The denominator of the productivity equation — units of work time — is even more spurious. Government data on work schedules are woefully out of touch with reality — especially in America's largest occupational group, the professional and managerial segments, which together account for 35 percent of the total work force.

For example, in financial services, the Labor Department tells us that the average workweek has been unchanged, at 35.5 hours, since 1988. That's patently absurd. Courtesy of a profusion of portable information appliances (laptops, cell phones, personal digital assistants, etc.), along with near ubiquitous connectivity (hard-wired and now increasingly wireless), most information workers can toil around the clock. The official data don't come close to capturing this cultural shift.

As a result, we are woefully underestimating the time actually spent on the job. It follows, therefore, that we are equally guilty of overestimating white-collar productivity. Productivity is not about working longer. It's about getting more value from each unit of work time. The official productivity numbers are, in effect, mistaking work time for leisure time.

Sounds right to me.