We have described the construction of a set of citations from USPTO patents, 1947-2018, to papers 1800-2018 from the Microsoft Academic Graph. The open nature of MAG makes it possible for us to share these patent-to-paper citations for use by other researchers. We moreover
characterize the performance of our linkage algorithm, characterizing positive and false-negative rates for linkages at each confidence level.
The general availability of patent citations to science will enable researchers to pursue a number of research agendas that were previously difficult to attempt, at least at scale. In the introduction we noted three areas the researchers have pursued: 1) describing the process of searching for innovations 2) characterizing the nature of R&D portfolios 3) the localization of spillovers from academia to industry. We conclude by sketching additional research questions that could be answered using PCS, including recent papers that further this agenda.
Reliable counts of scientific references in patents
Before proceeding, it is worthwhile to document what information is available to researchers in this dataset that was not generally available from the raw patent records. Previously,
researchers have been able to download the non-patent references from the front page of U.S.
patents in their raw, unstructured form. Absent additional processing, the general applicability of these data is to assemble a count of the non-patent references but without regard to the nature of the references (as in Fleming & Sorenson, 2004). As shown in Table 1, and as discussed more generally by Callaert et al. (2011), a large percentage of non-patent references are not scientific in nature but correspond to product brochures, actions of the patent office, press releases and other news items, or legal proceedings. Therefore, a key contribution of this dataset is to enable researchers to assemble a much more accurate count of scientific references in patents.
As one example, Kneeland, Schilling, & Aharonson (2019) use these data to examine the process by which inventors in firms come up with non-incremental innovations, finding that
“outlier” patents have more citations to science. Importantly, they find stronger results when
using the count of PCS from these data than when simply counting the overall number of NPL citations. Arora, Belenzon, and Suh (2019) use these data to expand the concept of firms’
technological search into markets for technology. Beyond merely citing articles they find relevant, firms can engage in transactions to acquire intellectual property (i.e., patents) they deem valuable. They report that patents more reliant on science (as measured by the count of PCS) are considerably more likely to be traded than those lacking scientific references. Two separate teams of authors use these and similar PCS to associate the count of scientific references in a focal patent with the monetary value of a patented invention (Watzinger & Schnitzer, 2019;
Poege et al., 2019). Whereas these authors would have had to use simple counts of NPL citations, their results are more reliable because they use actual counts of PCS.
Counts of scientific references from patents to a focal article
Not only does this dataset enable a more true count of citations to science in a patent; it enables the researcher to know how many citations to a focal paper come from the front pages of patents. Such analysis is impossible with a raw count of NPL citations, even if one decomposes NPLs into scientific and non-scientific. Rather, one must link the scientific NPL citation to the actual paper. The availability of these linkages enables research previously only possible for research teams that invested time in constructing the patent-to-paper linkages.
As an example, Bikard & Marx (2019) deepen our understanding of biases and heuristics involved in firms’ search for external technologies by counting the number of patent citations to each of more than 10 million articles. They find that firms tend to pay more attention to papers located in “hubs” of relevant industry R&D. They moreover characterize papers as being in more vs. less applied fields by counting the average number of PCS to all papers in the same field as the focal paper. Finally, the introduce a measure Journal Commercial Impact Factor (JCIF),
similar to the traditional Journal Impact Factor but which characterizes the commercial influence of a paper by counting citations from patents.
Enabling explicit comparisons between linked patents and papers
Beyond creating counts of scientific references in a given patent, or counts of scientific references to a given paper, these data enable explicit comparisons between each linked paper and patent. Such comparisons can be drawn across a wide variety of characteristics, including geography, age, institution, status, and other factors.
For example, Watzinger et al. (2019) take advantage of the ability to draw geographic comparisons between citing patents and cited articles to predict the impact of hiring a new professor on local commercial activity. They count patent citations to the papers published by a newly-hired professor—after s/he was hired—as compared to other shortlisted candidates who were not hired. By measuring the proximity of each citing patent to the cited paper, they are able to count the number of PCS that occurred in the local area of the focal university and distinguish this count from more distant citations. Beyond microgeography, opportunities abound to
understand cross-state or cross-country patterns of reliance on science.
Marx and Hsu (2019) leverage authorship comparison facilitated by this dataset to catalogue Science-Based Ventures (SBVs) in which a startup company founded by a university scientist commercializes that same discovery. Each patent assigned to a startup (as determined from CrunchBase or VentureXpert) is compared with all of the papers it cites to determine the level of overlap between the authors of the paper and the inventors on the patent. The count of SBVs in North America closely parallels the counts reported by the Association of University Technology Managers, but their data are available worldwide.
Many additional such comparisons are possible. Another application of authorship comparison would be to correlate the relative status of the paper cited (i.e., by the authors’
collective citation history vs. that of the patent inventors). One could alternatively rank the scientific status of a patent according to the average JIF of cited articles, average number of citations to cited articles, or other measures. Do firms rely on the “usual suspects” when citing scientific literature, or do they unearth less-well-trodden discoveries, and how does this practice relate to the novelty of the patented invention?
In addition to comparing authorship, one can compare institutional affiliation of the paper with that of the patent assignee (noting, of course, that papers may have multiple affiliations and patents may have multiple assignees). Doing so may be a useful bookkeeping exercise for researchers who want to exclude “self-citations”; more broadly, however, differentiating internal vs. external citations can open a window into how insular firms’ reliance on science is. Young firms likely have little internal science to rely upon, but does this pattern change as firms age?
What explains which firms continue to absorb external knowledge with those that focus inward, and do these practices predict differences in market performance?
Likewise, what leads firms to rely on older vs. more recent science in their R&D process?
Comparing the time lag between the citing patent and the cited paper could afford insight into firms’ and inventors’ preferences for well-established vs. cutting-edge science. Individual authors or inventors’ mobility, including exogenous limits on their mobility such as non-compete
agreements (Marx, Strumsky, & Fleming, 2009), could be used to assess the impact on science reliance by the influx of “new blood” into the R&D staff of a firm.
Finally, comparisons can be drawn by field. Which inventors cite science from their own field, and who recombines scientific inventions more broadly? Does the nature of creativity
impact firm performance or the careers of inventors? To this end, some sort of crosswalk between patent classifications and paper categories must be assembled.
Closing remarks
Work to date may only scratch the surface of possible paths utilizing PCS. Invention occurs in two largely distinct, yet somewhat overlapping spheres: the practice of “open science”
predominantly in academia; and the commercial realm, in which temporary monopolies can be secured. These worlds increasingly overlap as firms not just patent but publish, and as
universities lay legal claim to the allegedly-open creations of their employees. (One might observe, somewhat ironically, that much if not most “open” science is paywalled and the review process fully opaque whereas the patenting process—at least in the U.S.—is exceedingly
transparent with all documentation freely available.) Exploring the relationship between these spheres of invention can be challenging because publishing and patenting involve separate work products and, largely, separate actors. Perhaps the most important promise of PCS is to bridge those spheres by linking patents to papers and inventors to authors. What is the topology of the cross-community networks of authors who patent and inventors who publish? Which ideas originate in academia and then migrate to industry, and when does the reverse process take place? Our hope is that a broad set of researchers can attack these and other questions now that they are more easily able to assess reliance on science.
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Table 1: Ten randomly-sampled non-patent references from the front page of U.S. patents.
Patent # Unstructured reference PCS
6223284 Compaq Computer Corporation, "Compaq product information, bulletin, Proliant family of servers section 8,.Copyrgt. 1994 Compaq Computer Corporation, Feb. 2, 1995, pp. 1-6. N 9834791 Eisenschmidt et al., "Developing a programmed restriction endonuclease for highly
specific DNA cleavage," Nubcleic Acids Res., 33(22):7039-47 (2005). cited by applicant. Y 8009111 John P. Gianvittorio and Yahya Rahmat-samii, "Fractal element antennas: a compilation
of configurations with novel characteristics," IEEE, 4 pages, 2000. cited by other.
Y 9113925 Dald et al., "Accidental burns", JAMA, Aug. 16, 1971, vol. 217, no. 7, pp. 916-921. cited
by applicant. Y
9782195 "Fenestration revisited"", John A. Elefteriades, MD, et al.--Arch Surg--vol. 125--Jun.
1990--pp. 786-790. cited by applicant. Y
5383140 "User's manual, four-bit microcontroller and peripheral memory, tlcs-47e/47/470/470a""
(portions of title are in the Japanese language), pp. 5-211 through 5-223 and unnumbered final page, published by Toshiba corporation, dated 1991.
N
D699952 US. appl. no. 13/783,109, filed Mar. 1, 2013, Yang et al. cited by applicant. N 9484093 response to office action dated Aug. 5, 2016 in U.S. appl. no. 14/715,586. Cited by
applicant. N
9518078 Wolff, Manfred e. ""Burger's medicinal chemistry, 5ed, part i"", John Wiley & Sons,
1995, pp. 975-977. cited by examiner. Y
8980864 Saenz-Badillos, J. et al., RNA as a tumor vaccine: a review of the literature. Exp
Dermatol. jun. 2001;10(3):143-54. cited by applicant. Y
Table 2: The top 20 journals by the number of PCS.
# PCS Journal
428,363 Proceedings of the National Academy of Sciences of the United States of America 289,561 Journal of Biological Chemistry
284,282 Science 260,491 Nature
168,345 Journal of the American Chemical Society 166,660 Applied Physics Letters
Table 3: The top 20 papers most frequently cited by USPTO patents.
# PCS Title First author Journal Year
4,783 less than additive epistatic interactions of quantitative trait loci in tomato y eshed Genetics 1996 4,601 linkage disequilibrium and fingerprinting in sugar beet t kraft Theoretical and Applied Genetics 2000 4,242
deciphering the message in protein sequences tolerance to amino acid
substitutions james u bowie Science 1990
3,754 single amino acid substitution altering antigen binding specificity stuart rudikoff
Proceedings of the National Academy of
Sciences of the United States of America 1982 3,388
continuous cultures of fused cells secreting antibody of predefined
specificity g kohler Nature 1975
3,070
room temperature fabrication of transparent flexible thin film transistors
using amorphous oxide semiconductors kenji nomura Nature 2004
2,879
thin film transistor fabricated in single crystalline transparent oxide
semiconductor kenji nomura Science 2003
2,829
transparent thin film transistors using zno as an active channel layer and
their electrical properties satoshi masuda Journal of Applied Physics 2003
2,829 polymer stabilized liquid crystal blue phases hirotsugu kikuchi Nature Materials 2002
2,827
wide bandgap high mobility zno thin film transistors produced at room
temperature e fortunato Applied Physics Letters 2004
2,822
syntheses and single crystal data of homologous compounds in2o3 zno m m 3 4 and 5 ingao3 zno 3 and ga2o3 zno m m 7 8 9 and 16 in the in2o3
znga2o4 zno system noboru kimizuka Journal of Solid State Chemistry 1995
2,812
carrier transport in transparent oxide semiconductor with intrinsic
structural randomness probed using single crystalline ingao3 zno 5 films kenji nomura Applied Physics Letters 2004 2,795 field effect transistor on srtio3 with sputtered al2o3 gate insulator kazuo ueno Applied Physics Letters 2003 2,794
modulated structures of homologous compounds inmo3 zno m m in ga m
integer described by four dimensional superspace group chunfei li Journal of Solid State Chemistry 1998 2,791
crystallization and reduction of sol gel derived zinc oxide films by
irradiation with ultraviolet lamp naoko asakuma Journal of Sol-Gel Science and Technology 2003 2,789
amorphous oxide semiconductors for high performance flexible thin film
transistors kenji nomura Japanese Journal of Applied Physics 2006
2,786 42 1 invited paper improved amorphous in ga zn o tfts ryo hayashi
Society for Information Display International
Symposium 2008
2,783 dry etching of zno films and plasma induced damage to optical properties jun-beom park Journal of Vacuum Science & Technology B 2003 2,781 a ferroelectric transparent thin film transistor mwj menno prins Applied Physics Letters 1996
Table 4: Precision (1 – false positives) in a random sample of 100 PCS linkages per confidence level.
Table 5: Recall (1 – false negatives) as measured against 501 known-good references
(1) (2) (3) (4) (5)
Figure 1: Average number of citations to science per patent, by grant year
Figure 2: Average number of citations to science per patent, 1947-2018, broken down by assignee type.
01234
# PCS per patent
1940 1960 1980 2000 2020
year patent granted:
05101520
1940 1960 1980 2000 2020
grantyear
Government Corporation University Lone Inventor
Figure 3: Citations to science per patent, by patent grant year and technical classification
05101520
1940 1960 1980 2000 2020
grantyear
Human Necessities Operations and Transport Chemistry and Metallurgy Textiles
Fixed Constructions Mechanical Engineering
Physics Electricity
Figure 4: Distribution of confidence scores for PCS linkages
Figure 5: PCS linkage algorithm performance, recall vs. precision
98.6% 98.8% 99.0% 99.2% 99.4% 99.6% 99.8% 100.0% 100.2%
recall (1 -false negative rate)
precision (1 - false-positive rate)
(3) (4)
Appendices for Reliance on Science in Patenting:
USPTO Front-Page Patent Citations Since 1947
Matt Marx & Aaron Fuegi Appendix 1: Details of algorithm implementation
First, we standardize lexically both the structured and unstructured source data for analysis.
Second, we hash the unstructured source data into millions of subsets which can then be
examined in parallel. Third, we execute loose, computationally-inexpensive matching to generate a large number of potential PCS linkages. Fourth, we apply computationally-expensive scoring techniques to determine the likelihood that each potential PCS represents an actual PCS, and assign a confidence score to the linkage. The following sections describe each step in turn.