R&D and the Productivity Slowdown

The question I shall address in this pa-per is: Can the slowdown in productivity growth be explained, wholly or in part, by the recent slowdown in the growth of real R&D expenditures? But first we have to review the following questions: I) What is to be explained? Which productivity and what slowdown? 2) What is the mechanism by which R&D could have contributed to this slowdown? 3) What did happen to R&D in the relevant period? Besides traversing this somewhat familiar ground and reviewing some of the recent literature on this topic, I shall also report on some estimates of my own. The direct answer to the opening question is "probably not." But how we get there needs documenting and may prove instructive on its own merits.