To what extent are firms kept out of a market by patents covering related technologies? Do patents held by potential entrants make it easier to enter markets? We estimate the empirical relationship between market entry and patents for 27 narrowly defined categories of software products during...

This paper presents the results of a study of the determinants of research productivity in the pharmaceutical industry. Using disaggregated, internal firm data at the research program level from ten major pharmaceutical companies, we find no evidence of increasing returns to scale at either the...

This paper describes the database on U.S. patents that we have developed over the past decade, with the goal of making it widely accessible for research. We present main trends in U. S. patenting over the last 30 years, including a variety of original measures constructed with citation data,...

Building on insights gained from interviewing administrators and patent examiners at the United States Patent and Trademark Office (USPTO), we collect and analyze a novel dataset on patent examiners and patent outcomes. This dataset is based on 182 patents for which the Court of Appeals for the...

While there is widespread agreement among economists and management scholars that knowledge spillovers exist and have important economic consequences, researchers know substantially less about the "micro mechanisms" of spillovers -- about the degree to which they are geographically localized,...

We develop a model of growth driven by successive improvements in 'General Purpose Technologies' (GPT's), such as the steam engine, electricity, or micro-electronics. Each new generation of GPT's prompts investments in complementary inputs, and impacts the economy after enough such compatible...

A survey of recent patentees was conducted to elicit their perceptions regarding the importance of their inventions, the extent of their communication with other inventors, and the relationship of both importance and communication to observed patent citations. A cohort of 1993 patentees were...

The extent to which new technological knowledge flows across institutional and national boundaries is a question of great importance for public policy and the modeling of economic growth. This paper develops a model of the process generating subsequent citations to patents as a lens for viewing...