>Ah. Here's a clue:
>
><http://www.bog.frb.fed.us/pubs/feds/1999/199957/199957abs.html>.
>
>>Measuring Temporary Labor Outsourcing in U.S. Manufacturing
>>Marcello Estevao and Saul Lach
>>1999-57
From the paper:
>Finally, while a simple analysis of the reported manufacturing
>payroll employment data would suggest that the expansionary period
>between 1992 and 1997 generated only about 550,000 manufacturing
>jobs, the inclusion of THS workers in our calculations elevates this
>figure to between 890,000 and 1,060,000. Moreover, the decline in
>manufacturing hours between the local peak in 1989 and 1997 - about
>1-1/4 percent - disappears once THS workers are taken into account.
>Depending on the point estimates used, manufacturing hours increased
>as much as 1-1/4 percent between 1989 and 1997.
>On this account, between 1991 and 1997 the average growth rate of
>labor productivity in the manufacturing sector was biased upward by
>1/2 percentage point per year. In other words, adjusting for the
>increase in the use of THS workers lowers the measured growth rate
>of productivity during this period from about 3.8 percent per year
>to 3.3 percent per year.
Doug