This paper explores the implications of a simple model of learning and innovation by firms. In this model R&D spillovers are partly determined by firms, rather than by the given economic environment. According to this approach the full effect of spillovers on research productivity of firms...

This paper develops a simple model of a polluting industry and an innovating firm. The polluting industry is faced with regulation and costly abatement. Regulation may be taxes or marketable permits. The innovating firm invests in R&D and develops technologies which reduce the cost of pollution...

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...