You can see the computer age everywhere but in the productivity statistics.

There is, as Robert Rubin, the treasury secretary, says, a "disjunction" between the mass of business anecdote that points to a leap in productivity and the picture reflected by the statistics.

After 2000, the country's metal-bashers somehow managed to raise their productivity growth by another notch, to 5.1% a year, according to the Bureau of Labour Statistics.