Innovation and Entrepreneurship Research

The Selection of Patents for Litigation

Motivated by Henkel and Zischka (2015) we develop a diverging expectations model based on Priest and Klein (1984) for the selection of patents for litigation. A first goal is to estimate the share of invalid patents in the patent population by fitting the model to empirical data for the European patent system, using data directly collected by the European Patent Office (EPO) as well as derived findings reported in the literature, such as the distribution of patent values, the share of patents being subject to litigation, the share of patents judged invalid in annulment, etc. (see, e.g., Harhoff et al. 2015). We believe that an explicit modeling of the selection mechanics allows for a deeper understanding and a more accurate such estimate than previous attempts [2]. Moreover, since the legal stability of patents constitutes a key parameter in intellectual property policy and management, we hope that our findings will contribute to a more substantiated assessment of the efficiency and hence the welfare of the patent system as a whole.


Harhoff, D., Scherer, F. M., and Vopel, K. (2003). Citations, Family Size, Opposition and the Value of Patent Rights. Research Policy, 32(8), 1343-1363.

Henkel, J., and Zischka, H. (2015). Why most patents are invalid – Extent, reasons, and potential remedies of patent invalidity.

Priest, G. L., and Klein, B. (1984). The Selection of Disputes for Litigation. The Journal of Legal Studies, 13 (1), 1-55.



Dr. Stefan Sorg


Prof. Dietmar Harhoff, Ph.D.