As patent data become more available in machine-readable form, an increasing number of researchers have begun to use measures based on patents and their citations as indicators of technological output and information flow. This paper explores the economic meaning of these citation-based patent...

As patent data become more available in machine-readable form, an increasing number of researchers have begun to use measures based on patents and their citations as indicators of technological output and information flow. This paper explores the economic meaning of these citation-based patent...

Evidence on the "funding gap" for R&D is surveyed. The focus is on financial market reasons for underinvestment in R&D that persist even in the absence of externality-induced underinvestment. The conclusions are that 1) small and new innovative firms experience high costs of capital that are...

We review the econometric literature on measuring the returns to R&D. The theoretical frameworks that have been used are outlined, followed by an extensive discussion of measurement and econometric issues that arise when estimating the models. We then provide a series of tables summarizing the...