Production Technology, Information Technology, and Vertical Integration Under Asymmetric Information
Patent citations are extensively used as a measure of patent quality. However, counting citations does not account for the fast that citations corne from patents of different qualities, and that some citations are of a higher quality than other citations. We propose and develop a citation index which takes into account the cumulative quality of the citing patents. We apply this index to the 2,139,314 utility patents granted in the U.S. between 1975 and 1999. We study the properties of this index by year and by technological category, and analyse the links between patents.Abstract:Patent citations are extensively used as a measure of patent quality. However, counting citations does not account for the fast that citations corne from patents of different qualities, and that some citations are of a higher quality than other citations. We propose and develop a citation index which t akes into account the cumulative quality of the citing patents. We apply this index to the 2,139,314 utility patents granted in the U.S. between 1975 and 1999. We study the properties of this index by year and by technological category, and analyse the links between patents.
