Researchers studying innovation increasingly use indicators based on patent citations. However, it is well known that not all citations originate from applicants—patent examiners contribute to citations listed in issued patents—and that this could complicate interpretation of findings in this literature. In 2001 the US Patent and Trademark Office (USPTO) began reporting examiner and applicant citations separately. In this paper, we analyze the prior art citations of all patents granted by the USPTO in 2001-2003. We show that examiner citations account for 63 per cent of all citations on the average patent, and that 40 per cent of patents have all citations added by examiners. We use multivariate regression and analysis of variance to identify the determinants of examiner shares. Examiner shares are highest for non-US applicants and in electronics, communications, and computer-related fields. However, most of the variation is explained by firm-specific variables, with the largest patent applicants having high examiner shares. Moreover, a large number of firms are granted patents that contain no applicant prior art. Taken together, our findings suggest that heterogeneity in firm-level patenting practices, in particular by high-volume applicants, has a strong influence on the data. This suggests that analysis of firm-level differences in patenting strategies is an important topic for future research.
The FreePint Family is a family of resources to help information workers be more effective, raise the value of information in their organisations and contribute to success.
'FreePint... provides most of my professional development because it won't come through work and [other resources] just don't cut it.'
FUMSI Forum: Do you have a research question? Post it to the FUMSI Forum, where professionals share Q&A and useful tips on how to Find, Use, Manage and Share Information. It's free.
FreePint Shop:
VIP LiveWire:
