Regular articleAn analysis of the evolution of science-technology linkage in biomedicine
Introduction
There is a longstanding policy interest in unraveling how knowledge generated from public research is used in the private-sector. Studies towards this goal have heavily focused on patent data and considered citations between patents as evidence of knowledge flow. Despite some criticism (Meyer, 2000), such notion has been widely accepted in the literature. Consequently, substantial attention has been paid to patents assigned to universities and other public organizations, examining how those patents are cited by other patents, especially by patents from companies (Rosell & Agrawal, 2009; Trajtenberg, Henderson, & Jaffe, 1997).
University patents, however, only account for a small portion of granted patents, and the main products of public research are scholarly papers rather than patents. Just as patents, papers can also be cited by patents, and indeed both the cited patents and cited papers are served as the “prior art” of a patent application, playing a significant role for patent examiner to determine the patentability of the application. There has been a large literature on both the patent-to-patent and the patent-to-paper citation linkage. Yet, systematic studies, as we shall present in this paper, have been relatively scarce.
Our primary interest in this work is in the life science sector. The last several decades have seen an unprecedented rapid progress of life science, both in basic scientific discoveries and clinical medicine. Recent studies have suggested that biotechnology and pharmaceutical patents have been the main driver for the overall growth of patents and exhibit a particularly prominent citation linkage to science (Mowery, Nelson, Sampat, & Ziedonis, 2004). This has prompted us to ask: How has the patent-to-paper citation linkage of life science patents changed over time? In particular, we aim to answer the following lines of research questions:
- 1.
How has the amount of citations to science changed over time? Does the change vary across different technology classes?
- 2.
On the cited side of the linkage, which countries and types of institutions produce the cited papers? Whether basic or applied research are more likely to be cited?
- 3.
On the citing side, to what extent company patents cite public science?
The rest of the paper is organized as follows. Section 2 discusses the context of our work. In Section 3, we describe the data source, selection of the cohort of patents analyzed in this work, and methods used to identify various properties of patents and cited papers. Section 4 presents the results of our analysis. Finally, we discuss and conclude in Section 5.
Section snippets
Literature review
This section briefly reviews three lines of literature that are closely related to our work. The first two are about knowledge flows as evidenced from patent-to-patent and patent-to-paper citations, and the third one presents some alternative interpretations other than knowledge flows.
Sample selection
The NBER patent database (Hall, Jaffe, & Trajtenberg, 2001) has been one of the major sources for information about U.S. patents. However, it only covers patents granted until 2006, whereas we want to extend to later patents. We therefore used patent data directly from the USPTO and parsed the downloaded XML files (https://bulkdata.uspto.gov/) to obtain bibliographic information of patents. The NBER dataset instead is used as an auxiliary source when we infer various attributes of patents.
As we
Summary statistics
Table 2 reports the overall statistics of NPRs cited in the 1, 088, 650 patents in our sample, grouped by their NBER subcategories. The first group of statistics in Table 2 concerns about the total number of patents. Chemical patents share 62.7%, and the rest are DM patents. Among chemical patents, resins and organic compounds are the two largest subcategories, whereas drug and surgery & medical instruments patents are most presented ones in the DM category. Overall only 252, 821 (23.2%)
Discussion
We have uncovered several empirical findings regarding how citations to science of US life science patents has changed over a 37-year period. From the prevalent perspective of viewing citation linkage as knowledge flow, this study is particularly important, because our results suggest a continuous linkage of public science to private sector inventions. First, the overall growth of life science patents are largely driven by the increase of drug and medical patents. The volume of citations to
Author contributions
Qing Ke: Conceived and designed the analysis, Collected the data, Contributed data or analysis tools, Performed the analysis, Wrote the paper.
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2023, Information Processing and ManagementCitation Excerpt :Conducting an in-depth exploration of S&T linkages can effectively detect technological opportunities (Robinson et al., 2013), construct innovation roadmaps (Xu et al., 2019b), measure knowledge diffusion (Wang et al., 2021d), identify the evolution of science and technology topics (Qi et al., 2018), and understand university-industry-government collaborations. Various studies have been performed (Guan & He, 2007; Verhoeven et al., 2016; Ke, 2020), and science-technology linkages analysis has been well recognized as a crucial prerequisite for theoretically grasping the S&T innovation laws, promoting the transformation of scientific outcomes, and optimizing S&T innovation policies (Xu et al., 2021). Academic publications refer to the knowledge sources in science (Wang and Li, 2021), while patents can characterize the technical fields of innovative knowledge applications (Ahmadpoor & Jones, 2017).