How valuable is patent protection? Estimates by technology field

I present evidence on the private value of patent rights in France for different technology fields and nationalities of ownership, using nonparametric techniques and a parametric model of patent renewal. The distribution of the value of patent rights is highly skewed, patent protection is a significant but not the major source of private returns to R&D, and these characteristics vary across technology fields. I compute the R&D cash subsidy that is equivalent to the value of patent rights, measure the variations in value over time, technology fields, and nationalities, and show that these differences are correlated with patent grant rates.