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

How do firms differ, and why do they di.er even within narrowly defined industries? Using evidence from six high-tech, manufacturing industries covering a 24-year period, we show that di.erences in sales, materials, labor costs and capital across firms can largely be summarized by a single,...

Since governments can influence the demand for a new abatement technology through their environmental policy, they may be able to expropriate innovations in new abatement technology ex post. This suggests that incentives for environmental R&D may be lower than the incentives for market goods...