Experience effects of patent examiners: an empirical study of the career length and citation patterns on triadic patents

Does a patent examiner rely more on external sources of information for prior art searches as the examiner becomes more experienced? This question is relevant to the policy debate because studies confirm that the seniority of examiners is associated with higher patent allowance rate in the U.S. However, little is known to date about how examiners’ citation behavior, particularly search behavior, is related to their experience. This paper first describes how examiner experience is related to the rate of patent allowance and repeated use of prior citations by the same examiner. Next, this paper analyzes how examiner experience is related to the extent of receiving spillover at the USPTO and the JPO. This paper uses an empirical methodology to identify examination spillovers from the European Patent Office (EPO) search result to the United States Patent and Trademark Office (USPTO) and also to the Japan Patent Office (JPO) in the sense that patent citations for rejection of a patent application tend to be “adopted” at a later office after the EPO issues search reports. The results show that more experienced examiners exhibit greater convergence of patent citations at the USPTO and at the JPO with the search report outcome at the EPO, although the spillover effect also depends on international patent application routes, such as the Patent Cooperation Treaty (PCT).