Daniel I. Rees, Jeffrey S. Zax and Joshua Herries, "Interdependence in
worker productivity", Journal of Applied Econometrics, Vol. 18, No. 5,
2003, pp. 585-604.

The data that we use in this paper were provided to us under a commitment to
confidentiality, both with regard to the data themselves and with regard to
the identity of the company. Researchers interested in using these data
should contact Jeffrey S. Zax, at zax@colorado.edu or at

  Department of Economics
  University of Colorado at Boulder
  256 UCB
  Boulder, CO
  80309-0256

for further information.