This paper explores the economic factors which determine the variation of research effort across firms. The intra-industry coefficient of variation of research intensity is much larger than those of traditional factors. We show that this important fact is consistent with the theoretical argument...

Patent counts are very imperfect measures of innovative output. This paper discusses how additional data-the number of years a patent is renewed and the number of countries in which protection for the same invention is sought - can be used to improve on counts in studies which require a measure...

Patent counts are very imperfect measures of innovative output. This paper discusses how additional data-the number of years a patent is renewed and the number of countries in which protection for the same invention is sought - can be used to improve on counts in studies which require a measure...