R&D depreciation, stocks, user costs and productivity growth for US R&D intensive industries

This paper estimates R&D depreciation rates for U.S. R&D intensive industries. R&D annually depreciates at; 18% for chemical products, 26% for nonelectrical machinery, 29% for electrical products, and 21% for transportation equipment. These depreciation rates lead to new estimates of the marginal (gross of depreciation) returns to R&D capital; 0.25 for chemical products, 0.31 for nonelectrical machinery, 0.34 for electrical products, and 0.27 for transportation equipment. R&D investment significantly contributed to productivity growth; virtually 100% in chemical products, 55% in nonelectrical machinery, 38 percent in electrical products, and 84% in transportation equipment.