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Article
| Review of Economics and Statistics
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November 2006
Patent Citations as a Measure of Knowledge Flows: The Influence of Examiner Citations
by
Juan Alcacer and Michelle Gittelman
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Abstract
Analysis of patent citations is a core methodology in the study of knowledge diffusion. However, citations made by patent examiners have not been separately reported, adding unknown noise to the data. We leverage a recent change in the reporting of patent data showing citations added by examiners. The magnitude is high: two-thirds of citations on the average patent are inserted by examiners. Furthermore, 40% of all patents have all citations added by examiners. We analyze the distribution of examiner and inventor citations with respect to self-citation, distance, technology overlap, and vintage. Results indicate that inferences about inventor knowledge using pooled citations may suffer from bias or overinflated significance levels.
Keywords: Patents;
Knowledge Sharing;
Management Analysis, Tools, and Techniques;
Technology;
Prejudice and Bias;
Change;