Triadic citations,country biases and patent value: the case of pharmaceuticals

Triadic patents minimise home bias effects in studies that focus on patent counts as a measure of innovative activity. Yet, biases in qualitative patent indicators have been largely neglected. This article advocates that forward patent citations, and triadic citations in particular, can illuminate further on home bias, self citations, and the speed of knowledge flows for drug patents published by the USPTO for the period 1980–2008. The evidence shows that triadic citations help to minimize the home bias in citations as well as to make patent quality more transparent. Also, it indicates that self citations and the age distribution of citations are important factors to consider when explaining cross-country differences in pharmaceutical citations.     

What is Special about Patent Citations? Differences between Scientific and Patent Citations

The emergence of pattent bibliometrics as a new branch of scientometrics necessitates a deeper understanding of the relationship between patents and papers. As this connection is established through the linkage between patents and research papers, one must have a clear idea of similarities and differences between patent and paper citations. This paper will investigate to what extent one can not only apply bibliometric methods to patents but also extend the existing interpretative framework for citations in research papers to the field of patent citations. After pointing out some parallels in the debates about the nature of citations in patents and scientific articles, the paper outlines those parts of bibliometric theory covering scientific citations that could be relevant to patent citations too. Then it highlights the specialties and peculiarities of patent citations. One major conclusion is that the general nature of a common framework for both scientific and patent citations would severely limit its usefulness, but research on academic citations might still be a great source of inspiration to the study of patent citations.     

Motivations for URL citations to open access library and information science articles

Summary We define the URL citations of a Web page to be the mentions of its URL in the text of other Web pages, whether hyperlinked or not. The proportions of formal and informal scholarly motivations for creating URL citations to Library and Information Science open access journal articles were identified. Five characteristics for each source of URL citations equivalent to formal citations were manually extracted and the relationship between Web and conventional citation counts at the e-journal level was examined. Results of Google searches showed that 282 research articles published in the year 2000 in 15 peer-reviewed LIS open access journals were invoked by 3,045 URL citations. Of these URL citations, 43% were created for formal scholarly reasons equivalent to traditional citations and 18% for informal scholarly reasons. Of the sources of URL citations, 82% were in English, 88% were full text papers and 58% were non-HTML documents. Of the URL citations, 60% were text URLs only and 40% were hyperlinked. About 50% of URL citations were created within one year after the publication of the cited e-article. A slight correlation was found between average numbers of URL citations and average numbers of ISI citations for the journals in 2000. Separating out the citing HTML and non-HTML documents showed that formal scholarly communication trends on the Web were mainly influenced by text URL citations from non-HTML documents.     

The citation impact outside references — formal versus informal citations

In this study the amount of “informal” citations (i.e. those mentioning only author names or their initials instead of the complete references) in comparison to the “formal” (full reference based) citations is analyzed using some pioneers of chemistry and physics as examples. The data reveal that the formal citations often measure only a small fraction of the overall impact of seminal publications. Furthermore, informal citations are mainly given instead of (and not in addition to) formal citations. As a major consequence, the overall impact of pioneering articles and researchers cannot be entirely determined by merely counting the full reference based citations.     

What do patent examiner inserted citations indicate for a region with low absorptive capacity?

Most studies of patents citations focus on national or international contexts, especially contexts of high absorptive capacity, and employ examiner citations. We argue that results can vary if we take the region as the context of analysis, especially if it is a region with low absorptive capacity, and if we study applicant citations and examiner-inserted citations separately. Using a sample from the Valencian Community (Spain), we conclude that (i) the use of examiner-inserted citations as a proxy for applicant citations, (ii) the interpretation of non-patent references as indicators of science-industry links, and (iii) the traditional results for geographical localization are not generalizable to all regions with low absorptive capacity.     

Citations to the “Introduction to informetrics” indexed by WOS,Scopus and Google Scholar

Google Scholar and Scopus are recent rivals to Web of Science. In this paper we examined these three citation databases through the citations of the book “Introduction to informetrics” by Leo Egghe and Ronald Rousseau. Scopus citations are comparable to Web of Science citations when limiting the citation period to 1996 and onwards (the citation coverage of Scopus)—each database covered about 90% of the citations located by the other. Google Scholar missed about 30% of the citations covered by Scopus and Web of Science (90 citations), but another 108 citations located by Google Scholar were not covered either by Scopus or by Web of Science. Google Scholar performed considerably better than reported in previous studies, however Google Scholar is not very “user-friendly” as a bibliometric data collection tool at this point in time. Such “microscopic” analysis of the citing documents retrieved by each of the citation databases allows us a deeper understanding of the similarities and the differences between the databases.     

Be known by the company you keep: Citations — quality or chance?

We examine the determinants of five year citations to papers published in the American Economic Review and the Economic Journal. Citations are positively related to page length and position in the journal. Both of these variables are consistent with the hypothesis that citations reflect paper quality, as is the number of subsequent self-citations. However, the publication of a major paper, as judged by subsequent citations, significantly increases the citations of other papers in an issue and this indicates the importance of chance in determining citations.     

The choice of examiner patent citations for refusals: evidence from the trilateral offices

Utilizing a novel methodology based on international family-to-family patent citation data, this paper directly compares X/Y patent citations (i.e., those cited as grounds for rejections, equivalent to “blocking patents” in the US) between major patent offices. Remarkable discrepancies between the offices were revealed, despite the common patentability criteria of novelty and inventive step to generate citations. This paper then introduces a simple cosine similarity measurement between a family of X/Y patent citations and all citations added globally to the same original application. How the discrepancies of X/Y patent citations at the European Patent Office (EPO) and the US Patent and Trademark Office (USPTO) relate to the characteristics of applications and longitudinal aspects of office actions were also examined. X/Y patent citations from both the EPO and USPTO commonly show that the range of patent application classes is positively correlated with divergent reasons for refusal, suggesting that costly examinations lead to diversified X/Y patent citations. One novel methodological feature of this paper is that examiner citations across jurisdictions are comparable if we employ family-to-family citations and common criteria for the X/Y citation category. Furthermore, unlike the normal citation-generating process where a citing document adds citations to prior art only once, this paper represents the first attempt to analyze a citation network with multiple citing opportunities from separate parties. We find that the variance of citation linkages has a negative relationship with the ease in which different citers evaluate prior art in the same way, thereby providing a new perspective on the notion of breadth in citation impact.     

The effect of additional citations in the stability of Journal Citation Report categories

We use a new approach to study the ranking of journals in JCR categories. The objectives of this study were to empirically evaluate the effect of increases in citations on the computation of the journal impact factor (JIF) for a large set of journals as measured by changes in JIF, and to ascertain the influence of additional citations on the rank order of journals according their new JIFs within JCR groups. To do so, modified JIFs were computed by adding additional citations to the number used by Thomson-Reuters to compute the JIF of journals listed in the JCR for 2008. We considered the effect on rank order of a given journal of adding 1, 2, 3 or more citations to the number used to compute the JIF, keeping everything else equal (i.e., without changing the JIF of other journals in a given group). The effect of additional citations on the internal structure of rankings in JCR groups increased with the number of citations added. In about one third of JCR groups, about half the journals changed their rank order when 1–5 citations were added. However, in general the rank order tended to be relatively stable after small increases in citations.     

Effect on the journal impact factor of the number and document type of citing records: a wide-scale study

We studied the effect on journal impact factors (JIF) of citations from documents labeled as articles and reviews (usually peer reviewed) versus citations coming from other documents. In addition, we studied the effect on JIF of the number of citing records. This number is usually different from the number of citations. We selected a set of 700 journals indexed in the SCI section of JCR that receive a low number of citations. The reason for this choice is that in these instances some citations may have a greater impact on the JIF than in more highly-cited journals. After excluding some journals for different reasons, our sample consisted of 674 journals. We obtained data on citations that contributed to the JIF for the years 1998?C2006. In general, we found that most journals obtained citations that contribute to the impact factor from documents labeled as articles and reviews. In addition, in most of journals the ratio between citations that contributed to the impact factor and citing records was greater than 80% in all years. Thus, in general, we did not find evidence that citations that contributed to the impact factor were dependent on non-peer reviewed documents or only a few citing records.     

The matthew index—Concentration patterns and Matthew core journals

In this paper we extend our studies to the micro-structure of the Matthew effect for countries (MEC). The MEC allows the ranking of countries by their Matthew Index. The rank distribution of countries, observable only at a macro-level, has its roots in re-distribution processes of citations in every journal of the database. These re-distributed citations we call Matthew citations. Data for 44 countries and 2712 journals (based on theScience Citation Index) are analyzed. The strength of the contribution of the individual journals to the MEC (their number of Matthew citations) is skewly distributed. Due to this high concentration of the MEC we are able to define a new type of journal the Matthew core journal: 145 Matthew core journals account for 50% of the MEC. These journals carry a high potential of gaining a surplus of citations over what is expected and the risk of losing a high number of citations as well.     

Application of progressive nucleation mechanism for the citation behavior of individual papers of different authors

The basic concepts and equations of the progressive nucleation mechanism (PNM) are presented first for the growth and decay of items. The mechanism is then applied to describe the cumulative citations L and citations ΔL per year of the individual most-cited papers i of four selected Polish professors as a function of citation duration t. It was found that the PNM satisfactorily describes the time dependence of cumulative citations L of the papers published by different authors with sufficiently high citations ΔL, as represented by the highest yearly citations ΔL(max) during the entire citation period t (normal citation behavior). The citation period for these papers is less than 15?years and it is even 6-8?years in several cases. However, for papers with citation periods exceeding about 15?years, the growth behavior of citations does not follow the PNM in the entire citation period (anomalous citation behavior), and there are regions of citations in which the citation data may be described by the PNM. Normal and anomalous citation behaviors are attributed, respectively, to the occurrence and nonoccurrence of stationary nucleation of citations for the papers. The PNM also explains the growth and decay of citations ΔL per year of papers exhibiting normal citation behavior.     

Research and citation impact of publications by the Chemistry Division at Bhabha Atomic Research Centre

The paper analyses the citations to 1733 publications published during 1970–1999 by the Chemistry Division at Bhabha Atomic Research Centre, using Science Citation Index 1982–2003 as the source data. The extent of citations received, in terms of the number of citations per paper, yearwise break up of citations, domainwise citations, self-citations and citations by others, diachronous self-citation rate, citing authors, citing institutions, highly cited papers, the categories of citing documents, citing journals and distribution of citations among them etc. are determined. During 1982–2003 chemistry Division publications have received a total of 11041 citations. The average number of citations per year was 501.86. The average number of citations per publication was 6.37. The highest number of citations received were 877 in 2001. The citation rate was peaked during 1990–2003 as maximum 9145 (82.82%) citations were received during the period. Total self-citations were 3716 (33.66%) and citations by others were 7325 (66.34%). Mean diachronous self-citation rate was 36.16. Citation time lag was zero for 144 (15.52%) papers and one year for 350 (37.72%) papers. Single authored publications (168) have received 456 (4.13%) citations and 1565 multi-authored publications have received 10585 (95.87%) citations. The core citing authors were: J. P. Mittal (695) followed by V. K. Jain (524), H. Mohan (471), T. Mukherjee (307), R. M Iyer (253), H. Pal (251), J. V. Yakhmi (211), A. V. Sapre (174), D. K. Palit (161), N. M. Gupta (128), and S. K. Kulshrestha (116). Citation life cycles of four highly cited papers was discussed. The core journals citing Chemistry Division publications were: J. Phys. Chem.-A (436 citations), Chem. Phys. Lett. (372), J. Phys. Chem. (355), J. Chem. Phys. (353), J. Organomet. Chem. (285), J. Phys. Chem.-B (279), J. Photochem. Photobiol.-A (263), Langmuir (245), J. Am. Chem. Soc. (226), Physica-C (225), Radiat. Phys. Chem. (217), Inorg. Chem. (215) and Indian J. Chem.-A (207).     

Web of Science with the Conference Proceedings Citation Indexes: the case of computer science

Google Scholar and Scopus are recent rivals to Web of Science. In this paper we examined these three citation databases through the citations of the book “Introduction to informetrics” by Leo Egghe and Ronald Rousseau. Scopus citations are comparable to Web of Science citations when limiting the citation period to 1996 and onwards (the citation coverage of Scopus)—each database covered about 90% of the citations located by the other. Google Scholar missed about 30% of the citations covered by Scopus and Web of Science (90 citations), but another 108 citations located by Google Scholar were not covered either by Scopus or by Web of Science. Google Scholar performed considerably better than reported in previous studies, however Google Scholar is not very “user-friendly” as a bibliometric data collection tool at this point in time. Such “microscopic” analysis of the citing documents retrieved by each of the citation databases allows us a deeper understanding of the similarities and the differences between the databases.     

Indirect patent citations

Patent citations are extensively used as a measure of patent quality. However, counting citations does not account for the fact that citations come from patents of different qualities, and that citations are of variable qualities. We develop a citation index which takes into account the cumulative quality of the citing patents. We apply this index to the 2,139,314 utility patents granted in the U.S. between 1975 and 1999. We study the properties of this index by year and by technological category, and analyse the links between patents.     

Modeling motor vehicle crashes for street racers using zero-inflated models

Motor vehicle crashes are a leading cause of death for young people in the United States. Assessing which drivers are at a high risk of experiencing a crash is important for the implementation of traffic regulations. Illegal street racing has been associated with a high rate of motor vehicle crashes. In this study, we link Utah statewide driver license citations and motor vehicle crash data to evaluate the rate of crashes for drivers with street racing citations relative to other drivers. Using a zero-inflated negative binomial model we found that drivers with no citations are approximately three times more likely to be at zero risk of a crash compared to drivers with street racing citations. Moreover, among drivers at non-negligible risk of crash, cited street racers are more likely to be involved in a crash compared to drivers without citations or those cited for violations other than street racing. However, drivers with increased numbers of non-street-racing citations experience crash risks approaching those of the cited street racers.     

Examiner trust in applicants to the European Patent Office: country specificities

Indicators based on the probability of applicant citations in patents have been used to emphasize the importance of distinguishing applicant and examiner citations. However, the interpretation of these indicators and of the presence of applicant citations in European Patent Office (EPO) examiner reports is still uncertain. Based on interviews with patent examiners and patent applicants, we develop the idea that applicant citations in EPO examiner reports indicate examiner trust in applicants, and that this trust varies according to national patterns. Using EPO data for over 3,500,000 citations during 1997–2007, we verify that examiner trust in applicants is higher in granted patents. Examiners trust applicants from scientifically or economically strong countries, from member states of the European Patent Organization, and from the same country of the examiners.     

Publication trends in materials science: a global perspective

This paper attempts to highlight quantitatively and qualitatively the growth and development of world literature on materials science in terms of publication output and citations as per Web of Science (2006–2010). The objective of the study was to perform a scientometric analysis of all materials science research publications in the world. The parameters studied include growth of publications and citations, continent-wise distribution of publications and citations, country-wise distribution of publications, domain-wise distribution of publications and citations, publication efficiency index, distribution of publications and citations according to number of collaborating countries, variation of mean impact factor in materials science domains, identification of highly cited publications and highly preferred journals, quality of research output and application of Bradford’s law.     

Computer models for identifying instrumental citations in the biomedical literature

The most popular method for evaluating the quality of a scientific publication is citation count. This metric assumes that a citation is a positive indicator of the quality of the cited work. This assumption is not always true since citations serve many purposes. As a result, citation count is an indirect and imprecise measure of impact. If instrumental citations could be reliably distinguished from non-instrumental ones, this would readily improve the performance of existing citation-based metrics by excluding the non-instrumental citations. A citation was operationally defined as instrumental if either of the following was true: the hypothesis of the citing work was motivated by the cited work, or the citing work could not have been executed without the cited work. This work investigated the feasibility of developing computer models for automatically classifying citations as instrumental or non-instrumental. Instrumental citations were manually labeled, and machine learning models were trained on a combination of content and bibliometric features. The experimental results indicate that models based on content and bibliometric features are able to automatically classify instrumental citations with high predictivity (AUC = 0.86). Additional experiments using independent hold out data and prospective validation show that the models are generalizeable and can handle unseen cases. This work demonstrates that it is feasible to train computer models to automatically identify instrumental citations.