Do later citations to an earlier patent prove monetary value?
In November 2016, the Hon. Jan E. DuBois of ED Pa wrote of patent citation analysis:
However, the forward citation method of analysis has been recognized in the academic literature
as reliable since the 1990s.
A recent 2017 blog posting has the text
Citation analysis has been routinely used for several decades
to help assess patent quality and determine how patents impact
the competition and affect the world at large. A greater number
of forward citations for a given subject (published application or issued patent)
may imply its importance in a given technical space, its monetary value, its potential
for being infringed, or its shared interest by others in the technology.
The first text asserts "reliability" but the second asserts "routine use" that "may imply"
the importance of a highly cited patent.
which includes the text:
See also the 2010 IPBiz post
The citations found in patents: do references cited by the applicant matter?
, which contains a reference to a 1990s paper severely criticizing the use of patent citation analysis:
Simmons, Edlyn S.; Lambert, Nancy. "Comparing grapes and watermelons." ChemTech 23 (6), 1993, p. 51-59.
**Note separately the paper titled -- The Doctrine of Equivalents: Hilton Davis and Pioneering Patents -- [Intellectual Property Today, p. 10 (December 1996), available on LEXIS, which includes the text criticizing the patent citation work of Breitzman and Narin ("BN"):
In the March, 1996 issue of The Law Works, Breitzman and Narin ("BN") presented the argument "that very highly cited patents, patents of 'Pioneering Class' citation frequency, may be entitled to a broad interpretation of their claims, as are Pioneer patents." BN cited various studies that "support the notion of the technological importance of the inventions represented by highly cited patents." They noted that "there is a strong statistical association between pioneering patents and high citation frequency, just as there is a strong statistical association between high citation in patents and their technological importance."
In a letter in the November, 1996 issue of The Law Works, BN acknowledged that there were worthless patents that have received a lot of citations, just as there are important patents that have received few citations. Thus, the presence of many citations, by itself, does not prove value, and the absence of citations does not prove lack of value.
Nevertheless, BN find it inexplicable that 64 non-self-citations (out of 165 total cites) for US 4,105,776 don't strike me as extraordinary. My answer is that the number of citations for any patent, in the absence of an analysis of the citations, is insufficient to prove value. A few examples are in order.
In the November, 1996 letter, BN point to an article by Narin and Frame that was featured in the August 11, 1989 issue Science (which they consider "possibly the most prestigious of the thousands of U.S. research journals") n7. According to the ISI database (Dialog 434), this article has been cited 6 times. An article by Ebert in a 1990 issue of Science n8 has been cited 23 times. I would submit that the value of neither article is given by the number of citations.
n7 The Science article pertained to the growth of Japanese science. Narin's work on high citations of Japanese patents was discussed in Business Week (p. 57 of Aug. 9, 1993 issue), in the Jiji Press Ticker (May 28, 1991), Business America (Vol. 110, p. 13, Sept. 25, 1989 issue) and the New York Times (p. A1 of March 7, 1988 issue). He discussed the poor citation of Soviet work in Science, p. 629 (Feb. 8, 1985). Narin recently published an article "Biblometric Performance Measures" in Scientometrics, 1996, 36, 293-310; the abstract notes "The key measure is whether an agency is producing or supporting highly cited papers and patents."
n8 Science, 247, 1469 (1990).
BN referred to a 1986 article by Eugene Garfield, "Do Nobel Prize Winners Write Citation Classics?" For reference, I include herewith the total (first author) citation count for the three Nobel Prize winners in Chemistry in 1996, who won for their work on buckminsterfullerene (C60; "buckyball"): R.E. Smalley (1715), H. W. Kroto (3754), and R. F. Curl (1464). For comparison, I give numbers for past chemistry laureates: L. Pauling (23,187), P. J. Flory (19,173), G. A. Olah (11,795) and H. Taube (1785) and other chemistry professors J. P. Collman (9376), J. I. Brauman (1009), and N. H. Nachtrieb (351) n9.
n9 These prestigious authors presumably publish in primarily prestigious journals. Garfield has noted that only 100 journals (out of 3,400 indexed journals in SCI) account for 44% of cited articles.
In the November, 1996 letter, BN refer to the case I discussed (Gordon and Breach v. AIP) as "one rather old law suit", even though the case is still pending n10. This case was one example of many which illustrated potential issues with citation analysis n11.
n10 Summary judgment matters were disposed of in 859 F. Supp. 1521 (SD NY 1994) and in 905 F. Supp. 169 (SDNY 1995).
n11 We noted the issue of channeling in individual cites (the quote of Maddox and of Daubert) and in journal cites (Energy & Fuels). There are issues of improper cites and nonexistent cites, detailed in L. B. Ebert, FSTI, 15(3), in press, 1997. One can have cites to papers which are scientifically wrong, and perhaps even fraudulent (see C & E News, p. 7 (Nov. 4, 1996)). One notes that in the episode of the television show Law & Order which we cited in the July 1996 issue of The Law Works (p.6), as well as in the episode which aired Nov. 6, 1996, scientists who had all the superficial indicia of success, presumably including many citations, were, after detailed analysis, demonstrated to be villains. A moral of these episodes, which we adopt here, is that one has to look beyond the superficial before drawing conclusions. "Nose counts" of citations alone are just not enough to prove value.
BN made no comment about my discussion of the citation background for U.S. 3,900,554, issued on Aug. 19, 1975, "Method for the reduction of the concentration of NO in combustion effluents using ammonia" by Richard K. Lyon. In July, 1996, we noted that the patent had been cited in the "references cited" field of 92 patents, and in 133 patents overall. By October, 1996, the numbers had grown respectively to 98 and 141, with none of the recent patents by the assignee company. Although BN noted "a company that does not build on the prior art and technology that it has already patented would be one with a totally disorganized R&D effort", such arguably is the case with the '554 patent [see also Physics Today, pp. 59-60 (July 1987); Business Week, pp. 72-75 (April 2, 1990); Carbon 1995, 33, 1007-1010; Nature, 382, 17-18 (July 4, 1996)].
BN made no comments on the letters by Louis Robertson and Steve Mendelsohn in the July, 1996 issue of The Law Works. Furthermore, they have not fully responded to Paul Wille's argument in the April, 1996 issue. The patents that are listed in the "references cited" field of the first page of a patent originate from two sources: the examiner (PTO-892 form) and the applicant (PTO-1449) form. Of the first source, the examiner may cite a patent for what it teaches. There can be many uses made by the examiner of a patent reference. For example, I recently had an examiner cite a patent for its discussion of the prior art, not for the invention of the patent. Of the second source, the applicant is free to list patents for consideration by the patent office; as long as they comply with the rules, they will appear in the "references cited" field of the patent. There is no barrier to self-citation by the applicant. It is not clear that the method of BN distinguishes between references cited on a PTO-892 form and on a PTO-1449 form.
BN promise to review all the studies which have shown the importance of highly cited patents. There are many papers that have questioned the value of patent citation. n12
n12 Edlyn S. Simmons and Nancy Lambert, "Patent Statistics: Comparing Grapes and Watermelons", Proc. Montreux 1991 Int. Chemical Information Conference published in "Recent Advances in Chemical Information", Royal Society of Chemistry, Spec. Publ. 100, 1992.; see also Stuart M. Kaback, Nancy Lambert, and Edlyn S. Simmons, "Patent Citations: Source of Insight or Nothing to Get Excited About?", August 1994 meeting of American Chemical Society [this reference notes: "Patent citations turn out to be quite different in character from the citations we may be familiar with in the citation literature."]; E. Simmons, "Patent family databases 10 years later", Database, Vol. 18(3), Pg. 28, (June, 1995).
**One can find more than one paper criticizing patent citation analysis if one seriously looks.
link to the 2017 blog post: