**2.2. Data of scientific papers**

The Science Citation Index Expanded collection of the WoS database was used for this study. The WoS database contained bibliographic records of scientific papers which were published between 1981 and 2015. Each scientific paper in the WoS was classified to 1 of 22 scientific disciplines of the Essential Science Indicators. As for journals classified in "Multidisciplinary" by Clarivate Analytics, each of their papers was classified into 1 of the other 21 disciplines using their information on both forward and backward citations. Papers which were not classified into any of the 21 disciplines by the process were classified into "Multidisciplinary." They were excluded from the study because most of them obtained no or only a few citations and tended to be overestimated in the calculation of percentiles in the "Multidisciplinary" discipline. Disciplinary classification used in the study is shown in **Table 1**. Hereafter, I designated the codes for disciplines in the figures in this article.


**Table 1.** Disciplinary classification of the study.

### **2.3. Linking non-patent literatures in the Patstat to specific papers in the WoS**

All non-patent literatures appeared in the TLS214\_NPL\_PUBLN table of the Patstat and were matched to each bibliographic record of the WoS, so that citation links between them were identified. As a result of this process, 11,753,856 patent-paper citation links from Patstat to the WoS were identified. Number of WoS papers cited in the Patstat were 2,669,386, excluding duplications.

### **2.4. Attribution of institutional sectors to authors' organizations**

Institutional sectors of authors' organizations were needed to be attributed to analyze tendencies of patent-paper citations by institutional sector in the following sections. The Connection Table between "Web of Science Core Collection" (WoSCC) and "NISTEP Dictionary of Names of Universities and Public Organizations" publicly provided by National Institute of Science and Technology Policy, Japan, was used for the purpose. The table consists of IDs of scientific papers in the WoS (UT), organization names, and sector and some other information extracted from the NISTEP Dictionary of Names of Universities and Public Organizations. The table contains UTs of Japanese papers published between 1998 and 2015 of which document types were "Article" or "Review." Therefore, the scope of data used in the study was limited to these document types and publication years.

was secured for both patent-paper and paper-paper citations. The 6-year citation windows were defined in our previous study based on the criterion that at least a half of observable patent-paper citations could be grasped [9]. As for the earliest period (Period 1), 5-year citation windows were

As a result of the abovementioned process, a dataset for the study, which consisted of 6,962,541 records of the worlds' scientific papers published between 1998 and 2006, was obtained. The number of Japanese papers by institutional sector counted fractionally by the number of addresses appearing in each paper in the dataset was shown in **Figure 2**. Japanese universities published 72.4% of Japanese papers; public institutes and corporations published 13.3 and 8.6%, respectively. When rate of papers cited in patents in papers of each sector was calculated, the above orders were reversed; the rate of papers cited in patent of corporation,

Number of the worlds' papers published between 1998 and 2006 by discipline was shown in **Figure 3**. Both clinical medicine and chemistry showed large numbers of papers, and that

set according to [8] for observing citations from patents to patents citing target papers.

**Sector classification in NISTEP table**

institution, institute of local government

University National university, public university, private university, interuniversity research institute Public Institute National institute, government-affiliated public corporation/independent administrative

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public institutes, and universities was 21.6, 11.2, and 10.2%, respectively.

**2.6. Basic statistics of the dataset**

**Figure 1.** Time scheme of the study.

**Sector classification in** 

Corporation Corporation

**Table 2.** Institutional sector classification in the study.

**the study**

The sectoral classification of the research was derived by combining the categories of the NISTEP table as shown in **Table 2**.

#### **2.5. Time scheme of the study**

As a result of the preprocess mentioned above, a scheme of time periods for analysis was set as **Figure 1**. A 6-year citation window (7 years including publication year of the scientific papers)


**Table 2.** Institutional sector classification in the study.


**Figure 1.** Time scheme of the study.

**2.3. Linking non-patent literatures in the Patstat to specific papers in the WoS**

**2.4. Attribution of institutional sectors to authors' organizations**

**Code Discipline Code Discipline** AGS Agricultural sciences MTS Materials science BBI Biology and biochemistry MIC Microbiology

ECB Economics and business PHY Physics

GSC Geosciences SPA Space science

CHE Chemistry MOL Molecular biology and genetics CLM Clinical medicine NEB Neuroscience and behavior CPS Computer science PHT Pharmacology and toxicology

ENE Environment/ecology PLA Plant and animal science ENG Engineering PSS Psychiatry/psychology

IMU Immunology SSS Social sciences, general

limited to these document types and publication years.

NISTEP table as shown in **Table 2**.

**2.5. Time scheme of the study**

MAT Mathematics

154 Scientometrics

**Table 1.** Disciplinary classification of the study.

All non-patent literatures appeared in the TLS214\_NPL\_PUBLN table of the Patstat and were matched to each bibliographic record of the WoS, so that citation links between them were identified. As a result of this process, 11,753,856 patent-paper citation links from Patstat to the WoS were identified. Number of WoS papers cited in the Patstat were 2,669,386, excluding duplications.

Institutional sectors of authors' organizations were needed to be attributed to analyze tendencies of patent-paper citations by institutional sector in the following sections. The Connection Table between "Web of Science Core Collection" (WoSCC) and "NISTEP Dictionary of Names of Universities and Public Organizations" publicly provided by National Institute of Science and Technology Policy, Japan, was used for the purpose. The table consists of IDs of scientific papers in the WoS (UT), organization names, and sector and some other information extracted from the NISTEP Dictionary of Names of Universities and Public Organizations. The table contains UTs of Japanese papers published between 1998 and 2015 of which document types were "Article" or "Review." Therefore, the scope of data used in the study was

The sectoral classification of the research was derived by combining the categories of the

As a result of the preprocess mentioned above, a scheme of time periods for analysis was set as **Figure 1**. A 6-year citation window (7 years including publication year of the scientific papers) was secured for both patent-paper and paper-paper citations. The 6-year citation windows were defined in our previous study based on the criterion that at least a half of observable patent-paper citations could be grasped [9]. As for the earliest period (Period 1), 5-year citation windows were set according to [8] for observing citations from patents to patents citing target papers.

#### **2.6. Basic statistics of the dataset**

As a result of the abovementioned process, a dataset for the study, which consisted of 6,962,541 records of the worlds' scientific papers published between 1998 and 2006, was obtained. The number of Japanese papers by institutional sector counted fractionally by the number of addresses appearing in each paper in the dataset was shown in **Figure 2**. Japanese universities published 72.4% of Japanese papers; public institutes and corporations published 13.3 and 8.6%, respectively. When rate of papers cited in patents in papers of each sector was calculated, the above orders were reversed; the rate of papers cited in patent of corporation, public institutes, and universities was 21.6, 11.2, and 10.2%, respectively.

Number of the worlds' papers published between 1998 and 2006 by discipline was shown in **Figure 3**. Both clinical medicine and chemistry showed large numbers of papers, and that

was cited in the patents. Biology and biochemistry showed relatively smaller numbers of papers but showed comparatively close number of that cited in patents to clinical medicine and chemistry. Therefore, it showed a relatively higher rate of papers cited from patents per their papers. Seven disciplines surrounded by the dotted circle in **Figure 3** showed both small number of papers and that was cited in the patents. These disciplines were excluded from presentation in analysis 3 (Section 5), in which analysis was executed and presented by discipline. However, these seven disciplines were included in the calculation as in other analyses,

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Patent-paper citations are different from paper-paper citations in their statistic nature, such as their small amount compared to that of the latter. Therefore, some indicators developed in bibliometrics cannot be applied to patent-paper citations. To develop valid indicators, many aspects of their tendencies, especially which kind of papers were preferred to cite in patent, should be grasped. Although some studies tackled this question partially [4–6, 11], their analyses were restricted to the US patents [4, 5, 11] or limited numbers of "top" researchers [6]. Moreover, it is still unknown how papers were cited from patents of which feature values were relatively high (hereafter, they are called as high-feature-valued patents). Branstetter [12] addressed the question whether patents citing papers tended to be high feature valued. However, his approach was done from the patent side, not the paper side. Patent-paper citations from high-quality patents seemed to be more valuable from the view of possibility of

Here, I tried to grasp statistical tendencies of relationship between patent-paper citations from both all patents and those with high feature values. I intended to show the difference between them and to obtain basic knowledge of paper citations from high-feature-valued patents to develop valid indicators and show tendencies of (Japanese) scientific research from

Although many "quality indicators" have been proposed, it might be questionable whether all of them exactly reflect patent quality. Since they each focused on different aspects of patents, they might represent different features of patents, not all of which represent "quality." To facilitate a precise understanding of the results of analysis of patent-paper citations from patents with high-"quality indicators" (hereafter they are called as "feature values" since they were not necessarily representative of quality), and the meaning of the new indicators proposed in Section 5, here I tried to show differences in meaning of the various major patent feature values. In this subsection, I focused on the relationship between the three major feature values of patents: patent family size, forward citations (hereafter it is called as patent-patent forward

**3. Relationships between feature of papers and patent-paper** 

i.e., analysis 1 (Section 3) and analysis 2 (Section 4).

**citations (analysis 1)**

**3.1. Research question**

occurrence of innovation in many cases.

multi-aspects of patent-paper citations in the following sections.

**3.2. Relationship between feature values of patents and their patentability**

**Figure 2.** Number of Japanese papers by sector in 1998–2006.

**Figure 3.** Number of publications and papers cited in patents between 1998 and 2006.

was cited in the patents. Biology and biochemistry showed relatively smaller numbers of papers but showed comparatively close number of that cited in patents to clinical medicine and chemistry. Therefore, it showed a relatively higher rate of papers cited from patents per their papers. Seven disciplines surrounded by the dotted circle in **Figure 3** showed both small number of papers and that was cited in the patents. These disciplines were excluded from presentation in analysis 3 (Section 5), in which analysis was executed and presented by discipline. However, these seven disciplines were included in the calculation as in other analyses, i.e., analysis 1 (Section 3) and analysis 2 (Section 4).
