We develop a parsimonious model of innovating firms rich enough to confront firm-level evidence. It captures the dynamic behavior of individual heterogenous firms, describes the evolution of an industry with simultaneous entry and exit, and delivers a general equilibrium model of technological...

As distorted maps may mislead, Natural Language Processing (NLP) models may misrepresent. How do we know which NLP model to trust? We provide comprehensive guidance for selecting and applying NLP representations of patent text. We develop novel validation tasks to evaluate several leading NLP...

Research and development (R&D) is a key determinant of long run productivity and welfare. A central issue is whether a decentralized economy undertakes too little or too much R&D. We develop an endogenous growth model that incorporates parametrically four important distortions to R&D: the...

This paper examines the evidence on technology diffusion through trade in differentiated intermediate goods. Because intermediates are invented through costly research and development (R&D) investments, employing imported intermediates implies an implicit sharing of the technology that was...

R&D spillovers are, potentially, a major source of endogenous growth in various recent "New Growth Theory" models. This paper reviews the basic model of R&D spillovers and then focuses on the empirical evidence for their existence and magnitude. It reviews the older empirical literature with...

We examine the role of spillover learning in shaping the value of exploratory versus incremental R&D. Using data from drug development, we show that novel drug candidates generate more knowledge spillovers than incremental ones. Despite being less likely to reach regulatory approval, they are...