Measuring the Returns to R&D

This issue has been debated a lot recently. A new NBER working paper deals with the topic:

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 major results that have been obtained and conclude with a presentation of R&D spillover returns measurement. In general, the private returns to R&D are strongly positive and somewhat higher than those for ordinary capital, while the social returns are even higher, although variable and imprecisely measured in many cases.

Measuring the Returns to R&D, Bronwyn H. Hall, Jacques Mairesse, and Pierre Mohnen NBER Working Paper No. 15622, December 2009