Is the Time Allocated to Review Patent Applications Inducing Examiners to Grant Invalid Patents? Evidence from Microlevel Application Data

What Is a Patent Worth? Evidence from the U.S. Patent “Lottery”

“…We find that neither the characteristics of the applicant (in columns (1) and (2)) nor the characteristics of the application (in column (3)) predict the leniency of the examiner to whom the application was assigned, consistent with quasi‐random assignment. More experienced and more senior examiners are more lenient, all else equal (column (4)), consistent with previous evidence reported by Lemley and Sampat () and Frakes and Wasserman (), but this correlation does not invalidate our instrument to the extent that more experienced and more senior examiners are assigned applications quasi‐randomly, as our findings in Table suggest…”

Patents and the Success of Venture‐Capital Backed Startups: UsingExaminer Assignment to Estimate Causal Effects

“…Thus it is perhaps not surprising that there are substantial differences across examiners in how they process patent applications. As examiner promotions are associated with a higher case load, there are also differences in patent leniency across time for a given examiner, as found in Frakes and Wasserman [].…”

“…Intuitively, some firms ‘get lucky’ by drawing more lenient patent examiners, and I use variation in patents granted that are induced by the assignment to such examiners. I use a time‐varying measure of examiner leniency, as it has been found that examiners tend to get more lenient as they are promoted and their case loads increase (Frakes and Wasserman []) . The variation in examiner leniency used in this paper combines variation within examiners and variation between examiners.…”

“…Monotonicity makes sense in particular if we think of the variation in examiner leniency as primarily reflecting search effort – with some examiners spending more time searching the prior art than others, and hence being more likely to find prior art that limits the novelty or non‐obviousness of the application under review. Variation in search effort is to be expected as senior examiners are given a larger number of cases per year (Lemley and Sampat [], Frakes and Wasserman []).…”

“…As initially suggested by Cockburn, Kortum and Stern [], this can lead to considerable heterogeneity across patent examiners: there may be as many different patent offices as there are patent examiners. One type of patent examiner heterogeneity has been documented in recent work by Lemley and Sampat [] and Frakes and Wasserman []: more senior examiners cite less prior art and are more likely to grant patents…”