1. See, for example: R. M. Ranftl, “R&D Productivity,” Hughes Aircraft Company, Los Angeles, 1974 and 1978; Robert M. Ranftl, “Seven Keys to High Productivity,” Research Management, Sept.Oct. 1986, pp. 11–18; Roland W. Schmitt, “R&D in a Competitive Era,” Research Management, Jan.Feb. 1987, pp. 15–19; Lester C. Krogh, “How 3M Evaluates Its R&D Programs,” Research • Technology Management, Nov.Dec. 1988, pp. 10–14; Graham R. Mitchell and William F. Hamilton, “Managing R&D as a Strategic Option,” Research · Technology Management, May–June 1988, pp. 15–22; Mark G. Brown and Raynold A. Svenson, “Measuring R&D Productivity,” Research · Technology Management, July–Aug. 1988, pp. 11–15; Richard A. Pappas and Donald S. Remer, “Measuring R&D Productivity,” Research Management, May–June 1985, pp. 15–22.