Why Weak Patents? Rational Ignorance or Pro-'Customer' Tilt?

Abstract

The United States Patent and Trademark Office (USPTO) grants many weak patents that would be ruled invalid if subjected to more thorough scrutiny. Some observers see weak patents as evidence of the need for allocation of more resources to increase the accuracy of patent examinations. Others argue that the costs of such reform would outweigh the benefits; weak patents reveal the “rational ignorance” of the Patent Office; it is optimal to leave examiners unequipped to identify more weak applications, deferring the large costs of more definitive determination of validity until patents are litigated. Here we address the assumption underlying both positions: that examiners cannot distinguish weak patents from strong. We find that US examiners’ prior art searches reveal that they can and do identify many patents that are of dubious validity. They conduct a more intensive search for prior art for applications they accurately identify as weak, because they bear the burden of proof of non-patentability, but not of patentability. Our study suggests that the rules and procedures of the USPTO have forced examiners to grant many of these weak applications. Given the resources at hand, examiners possess information about the validity of their patents that society does not use. We do not find the balance of the marginal costs and benefits of information about patent validity that would characterize rational ignorance at the USPTO.