THE ROLE OF PATENT, CITATION AND OBJECTION STOCKS IN THE PRODUCTIVITY ANALYSIS OF R&D — USING JAPANESE COMPANY DATA

摘要

In this paper, I examine the role of patent stock, citation stock and objection stock in the analysis of R&D productivity and the exact interrelationships between those stocks by using new data on 100 large Japanese companies. I find, first, that citation and objection stock represent the knowledge stock of the company well, whereas patent stock itself is an ineffective proxy for the knowledge stock. Objection stock seems to be the best proxy for the knowledge stock. Second, citation and objection stocks are effective in playing the role of control factors for successful R&D stock, whereas patent stock is only effective if lags in R&D stock are incorporated. Third, citation and objection stocks are good proxies for controlling for the quality of patent stock. Citation stock seems to be the best variable for controlling for R&D stock and patent stock.