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http://doi.org/10.1007/s11192-012-0923-2
http://hdl.handle.net/10251/86315
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Leydesdorff, L.; Kushnir, D.; Rafols García, I. (2014). Interactive Overlay Maps for US Patent
(USPTO) Data Based on International Patent Classifications (IPC). Scientometrics.
98(3):1583-1599. doi:10.1007/s11192-012-0923-2.
Seediscussions,stats,andauthorprofilesforthispublicationat:https://www.researchgate.net/publication/232642278
InteractiveoverlaymapsforUSPatent(USPTO)
databasedonInternationalPatent
Classifications(IPC)
ArticleinScientometrics·October2012
DOI:10.1007/s11192-012-0923-2·Source:arXiv
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1
Interactive Overlay Maps for US Patent (USPTO) Data
Based on International Patent Classifications (IPC)
Scientometrics (in press)
Loet Leydesdorff,
a
* Duncan Kushnir,
b
and Ismael Rafols
c
,
d
Abstract
We report on the development of an interface to the US Patent and Trademark Office (USPTO)
that allows for the mapping of patent portfolios as overlays to basemaps constructed from
citation relations among all patents contained in this database during the period 1976-2011. Both
the interface and the data are in the public domain; the freeware programs VOSViewer and/or
Pajek can be used for the visualization. These basemaps and overlays can be generated at both
the 3-digit and 4-digit levels of the International Patent Classifications (IPC) of the World
Intellectual Property Organization (WIPO). The basemaps can provide a stable mental
framework for analysts to follow developments over searches for different years, which can be
animated. The full flexibility of the advanced search engines of USPTO are available for
generating sets of patents and/or patent applications which can thus be visualized and compared.
This instrument allows for addressing questions about technological distance, diversity in
portfolios, and animating the developments of both technologies and technological capacities of
organizations over time.
Keywords: map, USPTO, IPC, patent, classification, overlay
a
Amsterdam School of Communication Research (ASCoR), University of Amsterdam,
Kloveniersburgwal 48, 1012 CX Amsterdam, The Netherlands; loet@leydesdorff.net; http://www.leydesdorff.net; *
corresponding author.
b
Environmental Systems Analysis, Chalmers University of Technology, Göteborg, Sweden;
duncan.kushnir@chalmers.se.
c
SPRU (Science and Technology Policy Research), University of Sussex, Freeman Centre, Falmer
Brighton, East Sussex BN1 9QE, United Kingdom; i.rafols@sussex.ac.uk.
d
Ingenio (CSIC-UPV), Universitat Politècnica de València, València, Spain.
2
1. Introduction
Alongside scholarly publishing, patents have increasingly become an output of scholarly work.
The Bayh-Dole Act of 1980, among other things, granted to universities, small businesses, and
non-profit organizations the intellectual property rights to inventions that result from government
funding. Other countries followed this legislation and university transfer offices were established
to promote knowledge transfer in university-industry relationships. Using non-patent literature
references, Narin et al. (1997) signaled a more intense and closer linkage between patenting and
publishing in several fields of science and technology (Henderson et al., 2005). With increased
awareness of the emergence of a knowledge-based economy, the patent system became further
adapted to the publication system. With the 2011 “American Invents Act,” for example, the USA
brought its patenting system in line with the rest of the world by changing (as of 2013) from
“first to invent” to “first to file” as the basis for granting patents.
More generally, patents can also be considered as indicators of input into the economy.
Grilliches (1984) focused on patents as such indicators, and noted the different and sometimes
incompatible organization of various statistics (Grilliches, 1994:14). Jaffe & Trajtenberg (2002)
then used three million patents and 16 million citations in the USPTO database in a
comprehensive study of what these authors called “a window on the knowledge-based
economy.” However, oatents are indicators of invention; innovation presumes the introduction of
inventions into a market. Patents are thus developed in relation to two social contexts: the
sciences and markets (Klavans & Boyack, 2008).
Accordingly, patents are classified in terms of technologies and not by products or industries
(Jaffe, 1986).
1
The long chain between scientific discovery and technological and/or industrial
applications can sometimes be cut short by feedback mechanisms (Kline & Rosenberg, 1986;
Von Hippel, 1988), but the two processes are very different in terms of institutional incentives
(Rosenberg & Nelson, 1994). The rankings of universities that emerged in the early 2000s, for
example, did not include patenting among the indicators of excellence (Leydesdorff & Meyer,
2010).
In summary, patenting is an indicator of industrial activity more than of academic production
(Shelton & Leydesdorff, 2012). Whereas scholarly literature is mainly organized into journals,
patents are organized into patent classification systems. There are two major classification
systems: that used by the US Patent and Trade Office (USPTO), and the International Patent
Classifications (IPC) developed by the World Intellectual Property Organization (WIPO) in
1
Schmoch et al. (2003) provided a concordance table between International Patent Classifications (IPC) and
industrial classifications with the NACE codes (“Nomenclature statistique des activités économiques dans la
Communauté européenne”) used by the OECD.
3
Geneva. The latter was first developed for international patenting under the Patent Cooperation
Treaty (PCT) that has been signed by most countries of the world since its inception in 1970.
The European Patent Office (EPO) refined the IPC into the European Classification Systems
(ECLA) in partnership with the WIPO, the Organization for Economic Cooperation and
Development (OECD) in Paris, and the International Patent Documentation Center (INPADOC)
in Vienna. The OECD further developed the concept of patent families into “triadic patents,” that
is, those patents held in common by the USPTO, the EPO, and the Japanese Patent Office
(JPO).
2
“Triadic patents” are considered as the highest-quality patents, whereas national
patenting can be of mixed quality. Patents can be internationalized under the Patent Cooperation
Treaty (of the WIPO) and are then indicated as PCT patents.
The various patenting systems offer firms different routes for patenting: one can patent
nationally, internationally (at the WIPO’s PCT), or at the regional level such as the EPO. The
propensity to patent and the internationalization of patenting can be expected to differ among
nations, sectors, disciplines, etc. Among the national patents, USPTO patents are considered the
most valuable because of the competitiveness of the US market; the US is the world leader in
most technologies (Criscuolo, 2006). As technology indicators, US patents can be assumed to be
the most reliable because firms want to secure their intellectual property rights in this largest
market.
Like publications, patents can also be distinguished in terms of their numbers of citations, but
citation in the case of patenting may mean something different from citation in scholarly
literature. In addition to inventor citations, the examiner can attach citations to the front page of
the patent in order to ensure coverage of prior art because of the possibility to challenge patents
in court (Criscuolo & Verspagen, 2008). Since 2001, the full texts of patents allows one to
distinguishes between applicant and examiner citations in US patents, while the latter are
asterisked on the front pages of the patents (Alcácer et al., 2009).
3
The patenting system is thus
regulated more formally than the publication system.
Whereas journals organize scholarly literature in terms of disciplines and subdisciplines as latent
variables (which one can bring to the fore using, for example, factor analysis of the citation
matrix), patents are categorized manifestly by their patent classification systems. Citations
among journals and journal categories have been used successfully to map scientific literature
(Klavans & Boyack, 2009). Rafols et al. (2010) further developed an overlay technique that
2
“A patent family is a set of patents taken at various offices to protect a given invention. It is triadic when the
invention to which it refers has been the subject of a patent application at the European Patent Office (EPO) and the
Japan Patent Office (JPO), and the subject of the issue of a title of ownership at the United States Patent and
Trademark Office (USPTO). In other words, a triadic patent protects an invention on the U.S., European and
Japanese markets simultaneously.” Source: http://www.stat.gouv.qc.ca/savoir/indicateurs/triadiques/index_an.htm.
3
The program uspto1.exe can be used for downloading the citing patents using the routines available at
http://www.leydesdorff.net/indicators/lesson5.htm (Leydesdorff, 2004).
