Strategic Citation

Abstract

The candor of patent applicants is an important determinant of patent quality. This paper investigates whether patent applicants strategically withhold citations to material "prior art." Citation data suggest that applicants withhold between 21 and 32 percent of relevant citations. Variation in withholdings is explained by patent value and patent portfolio size. These data also highlight important differences across technology classes. In particular, firms are significantly less likely to withhold a citation when applying for chemical and drug patents. Robustness checks confirm that these results are not explained by patent examiner heterogeneity or by the nationality of the inventor.

Keywords: patents, citations

JEL Classification: O34