Lens or Prism? Patent Citations as a Measure of Knowledge Flows from Public Research / Michael Roach, Wesley M. Cohen.

Format:

Book

Author/Creator:

Roach, Michael.

Contributor:

National Bureau of Economic Research.

Cohen, Wesley M.

Series:

Working Paper Series (National Bureau of Economic Research) no. w18292.

NBER working paper series no. w18292

Language:

English

Physical Description:

1 online resource: illustrations (black and white);

Place of Publication:

Cambridge, Mass. National Bureau of Economic Research 2012.

Summary:

This paper assesses the validity and accuracy of firms' backward patent citations as a measure of knowledge flows from public research by employing a newly constructed dataset that matches patents to survey data at the level of the R&D lab. Using survey-based measures of the dimensions of knowledge flows, we identify sources of systematic measurement error associated with backward citations to both patent and nonpatent references. We find that patent citations reflect the codified knowledge flows from public research, but they appear to miss knowledge flows that are more private and contract-based in nature, as well as those used in firm basic research. We also find that firms' patenting and citing strategies affect patent citations, making citations less indicative of knowledge flows. In addition, an illustrative analysis examining the magnitude and direction of measurement error bias suggests that measuring knowledge flows with patent citations can lead to substantial underestimation of the effect of public research on firms' innovative performance. Throughout our analyses we find that nonpatent references (e.g., journals, conferences, etc.), not the more commonly used patent references, are a better measure of knowledge originating from public research.

Notes:

Print version record

August 2012.