We analyse the determinants of the decline in measured research productivity (the patent/R&D ratio) using panel data on manufacturing firms in the US for the period 1980-93. We focus on three factors: the level of demand, the quality of patents, and technological exhaustion. We first develop an index of patent ‘quality’ using detailed information on patents in the US in seven technology fields. Using a factor model, we construct a minimum-variance index based on four patent characteristics and show that using multiple indicators substantially reduces the measured variance in quality. We then show that research productivity at the firm level is negatively related to the patent quality index and the level of demand, as predicted by an optimizing model of R&D, and positively related to the stock market valuation of patented innovations held by firms.
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Paper provided by C.E.P.R. Discussion Papers in its series CEPR Discussion Papers with number
3623.
References listed on IDEAS Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
Zvi Griliches, 1984.
"Market Value, R&D, and Patents,"
NBER Chapters,
in: R & D, Patents, and Productivity, pages 249-252
National Bureau of Economic Research, Inc.
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