Global patent systems: Revisiting the national bias hypothesis

This paper revisits the literature providing empirical evidence that patent offices are biased in favor of their national applicants. If true, this “national bias” would be proof of disrespect of the national treatment principle, deeply rooted in several international patent treaties. Existing investigations are, however, subject to an important limitation: they focus only on grant rates, which in all likelihood is a potentially biased indicator of stringency because it is influenced by economic forces. This paper puts forward an alternative and more robust approach to test the national bias hypothesis, consisting in a detailed analysis of how the patent examination process is carried out for domestic and international applications. Relying on a unique database of 2,400 patent families filed simultaneously in three patent offices (EPO, JPO, and USPTO), the empirical analysis finds no evidence of national bias - in any of the three patents offices - throughout the examination process. These results reopen a debate that seemed to have reached a consensus so far. The lower grant rates of international applications are not caused by a discriminatory bias in the examination procedures but might rather be driven by economic forces that shape the propensity of international applicants to maintain their patent active.