For more information on multifactor productivity, see Productivity  Business Sector and Major Subsectors, BLS Handbook of Methods, Bureau of Labor Statistics (April 1997), pp. 89-98; and Edwin R. Dean and Michael J. Harper, The BLS Productivity Measurement Program, Bureau of Labor Statistics (July 5, 2000), paper presented to the NBER Conference on Research in Income and Wealth on New Directions in Productivity Analysis, March 20-21, 1998.