A bibliometric approach to the role of author self-citations in scientific communication

The present paper analyses the role of author self-citations aiming at finding basic regularities of self-citations within the process of documented scientific communication and thus laying the methodological groundwork for a possible critical view at self-citation patterns in empirical studies at any level of aggregation. The study consists of three parts; the first part of the study is concerned with the comparative analysis of the ageing of self-citations and of non-self citations, in the second part the possible interdependence between self-citations and foreign citations is analysed and in the third part the interrelation of the share of self-citations in all citations with other citation-based indicators is studied. The outcomes of this study are two-fold; first, the results characterise author self-citations - at least at the macro level - as an organic part of the citation process obeying rules that can be measured and described with the help of mathematical models. Second, these rules can be used in evaluative micro and meso analyses to identify significant deviations from the reference standards.     

Citation frequency: A biased measure of research impact significantly influenced by the geographical origin of research articles

Context. The use of citation frequency and impact factor as measures of research quality and journal prestige is being criticized. Citation frequency is augmented by self-citation and for most journals the majority of citations originate from a minority of papers. We hypothesized that citation frequency is also associated with the geographical origin of the research publication. Objective. We determined whether citations originate more frequently from institutes that are located in the same country as the authors of the cited publication than would be expected by chance. Design. We screened citations referring to 1200 cardiovascular publications in the 7 years following their publication. For the 1200 citation recipient publications we documented the country where the research originated (9 countries/regions) and the total number of received citations. For a selection of 8864 citation donor papers we registered the country/region where the citing paper originated. Results. Self-citation was common in cardiovascular journals (n = 1534, 17.8%). After exclusion of self-citation, however, the number of citations that originated from the same country as the author of the citation recipient was found to be on average 31.6% higher than would be expected by chance (p<0.01 for all countries/regions). In absolute numbers, nation oriented citation bias was most pronounced in the USA, the country with the largest research output (p<0.001). Conclusion. Citation frequency was significantly augmented by nation oriented citation bias. This nation oriented citation behaviour seems to mainly influence the cumulative citation number for papers originating from the countries with a larger research output.     

Self-citations at the meso and individual levels: effects of different calculation methods

This paper focuses on the study of self-citations at the meso and micro (individual) levels, on the basis of an analysis of the production (1994–2004) of individual researchers working at the Spanish CSIC in the areas of Biology and Biomedicine and Material Sciences. Two different types of self-citations are described: author self-citations (citations received from the author him/herself) and co-author self-citations (citations received from the researchers’ co-authors but without his/her participation). Self-citations do not play a decisive role in the high citation scores of documents either at the individual or at the meso level, which are mainly due to external citations. At micro-level, the percentage of self-citations does not change by professional rank or age, but differences in the relative weight of author and co-author self-citations have been found. The percentage of co-author self-citations tends to decrease with age and professional rank while the percentage of author self-citations shows the opposite trend. Suppressing author self-citations from citation counts to prevent overblown self-citation practices may result in a higher reduction of citation numbers of old scientists and, particularly, of those in the highest categories. Author and co-author self-citations provide valuable information on the scientific communication process, but external citations are the most relevant for evaluative purposes. As a final recommendation, studies considering self-citations at the individual level should make clear whether author or total self-citations are used as these can affect researchers differently.     

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).     

The efficiency of self-citations in economics

Summary Are prior self-citations an effective input in increasing a subsequent article's citation count? Examination of 418 articles in eight economics journals found that, after controlling for article length, journal and author quality, lead article position, and coauthorship, an author's prior stock of self-citations is not statistically related to a subsequent article's total citation count or the quality of the journals in which those citations appear. Self-citations that appear in prestigious high-impact economics journals have a statistically positive, but numerically small, effect on a subsequent article's total citation count and on the quality of the citing journal. The productive effect of a prior self-citation is inversely related to its age. Prior self-citations of the second author listed in a collaborative article have no significant effect on a subsequent article's total citation count or the quality of the economics journals in which those citations appear.     

Research performance indicators for university departments: A study of an agricultural university

The present bibliometric study extends previous work by focusing on the research performance of departments in the natural and life sciences, the social and behavioral sciences, and the humanities. The present study covers all 70 departments from one agricultural university, and several veterinary departments of a second university. The impact analysis was extended by including other types of documents than journal articles. For about a third of the departments, publications not covered in citation indexes accounted for at least 30% of the citations to their total oeuvre. To deal with different citation and publication habits in the various fields, both short-term and medium-term impact assessments were made. The commonly used three year window is not universally applicable, as our results show. The inclusion of self-citations forms an important source of error in the ratio of actual/expected impact. To cope with this, the trend and level of self-citations was compared at university level with that in a matched sample of publications. Moreover, at a departmental level, self-citation rates were used to detect departments with divergent levels of self-citation. The expected impact of journals accounted for only 18% of the variance in actual impact. Comparison of bibliometric indicators with two peer evaluations showed that the bibliometric impact analyses provided important additional information.     

Impact of country self-citations on bibliometric indicators and ranking of most productive countries

Scientometrics - The aim of the present work is to determine the share of country self-citations and to analyze its impact on total citations, average citation per paper, % cited publications and...     

Is citation analysis a legitimate evaluation tool?

A comprehensive discussion on the use of citation analysis to rate scientific performance and the controversy surrounding it. The general adverse criticism that citation counts include an excessive number of negative citations (citations to incorrect results worthy of attack), self-citations (citations to the works of the citing authors), and citations to methodological papers is analyzed. Included are a discussion of measurement problems such as counting citations for multiauthored papers, distinguishing between more than one person with the same last name (homographs), and what it is that citation analysis actually measures. It is concluded that as the scientific enterprise becomes larger and more complex, and its role in society more critical, it will become more difficult, expensive and necessary to evaluate and identify the largest contributors. When properly used, citation analysis can introduce a useful measure of objectivity into the evaluation process at relatively low financial cost.Modification of a chapter in E. Garfield:Citation Indexing: Its Theory and Application in Science, Technology and the Humanities, New York, Wiley, 1979.     

Exploring the analytical potential of comparing citing and cited source items

Summary Comparing properties of citing and cited source items opens a wide variety of analytical possibilities. In a study of citations among papers in the journal Scientometrics a number of analytical themes are identified. The analysis shows: the way in which a citation graph can be decomposed into different subparts; country specific citation patterns; the effects of self-citations and domestic citations; the mapping of cited author relationships using direct citation and co-citation links; and time slicing effects on impact ranking of countries and papers.     

Same same but different: self-citations identified through Scopus and Web of Science Core Collection

Self-citation is attracting wide attention in citation analysis research and research evaluation practice. However, the academic community’s views on self-citation are not uniform. If the number of self-citations should be calculated, it is critical to calculate it accurately and unambiguously. However, based on a case study of thirty papers published during 2014 and 2020 by the corresponding author of the study, we find that the numbers of self-citations identified through the automatic identification tools provided by Scopus and Web of Science Core Collection are confusing and inconsistent. We also put forward corresponding improvement suggestions to the stakeholders including these two authoritative bibliographic database providers at the end of this article.

     

Regional analysis on Chinese scientific output

Based on data from the Science Citation Index Expanded (SCIE) and using scientometric methods, we conducted a systematic analysis of Chinese regional contributions and international collaboration in terms of scientific publications, publication activity, and citation impact. We found that regional contributions are highly skewed. The top positions measured by number of publications or citations, share of publications or citations are taken by almost the same set of regions. But this is not the case when indicators for relative citation impact are used. Comparison between regional scientific output and R&D expenditure shows that Spearman’s rank correlation coefficient between the two indicators is rather low among the leading publication regions.     

Assessing insularity in global science

Most scientific research has some form of local geographical bias. This could be caused by researchers addressing a geographically localized issue, working within a nationally or regionally defined research network, or responding to research agendas that are influenced by national policy. These influences should be reflected in citation behavior, e.g., more citations than expected by chance of papers by scientists from institutions within the same country. Thus, assessing adjusted levels of national self-citation may give insights into the extent to which national research agendas and scientific cultures influence the behavior of scientists. Here we develop a simple metric of scientific insularism based on rates of national self citation corrected for total scientific output. Based on recent publications (1996?C2010), higher than average levels of insularism are associated with geographically large rapidly developing nations (Brazil, Russia, India, and China??the so-called BRIC nations), and countries with strongly ideological political regimes (Iran). Moreover, there is a significant negative correlation between insularism and the average number of citations at the national level. Based on these data we argue that insularism (higher than average levels of national self-citation) may reflect scientific cultures whose priorities and focus are less tightly linked to global scientific norms and agendas. We argue that reducing such insularity is an overlooked challenge that requires policy changes at multiple levels of science education and governance.     

Some bibliometric correlates of quality in scientific research

The following kinds of data were collected on three samples of cancer research literature representing three levels of quality: (1) collaboration as measured by the number of authors per paper, (2) quantitative productivity of countries, (3) diachronous citations covering the first five years of publication, (4) total self-citations, (5) proportions of self-citations made by first-named authors, and (6) the extent of dispersion of articles among journals. Analyses showed that as the number of authors per paper increases, the proportion of high quality papers also increases and the Collaborative Index can be used to measure quality in the aggregate. It was found that the quantity and quality of cancer research done in a country are positively related. All analyses of the citation data confirmed the hypotheses that highly rated papers are significantly more highly cited than average papers and the rates of uncitedness decline with quality. The proportion of self-citations to total citations decreases with increasing quality and, on average, first-named authors of quality papers cite them proportionally fewer times than first-named authors of run-of-the mill papers do. This study also shows that, as quality increases, the extent of literature scatter or dispersion increases.     

The influence of author self-citations on bibliometric macro indicators

In a recent paper the authors have studied the role of author self-citations within the process of documented scientific communication. Two important regularities such as the relative fast ageing of self-citations with respect to foreign citations and the “square-root law” characterising the conditional expectation of self-citations for given number of foreign citation have been found studying the phenomenon of author self-citations at the macro level. The goal of the present paper is to study the effect of author self-citations on macro indicators. The analysis of citation based indicators for 15 fields in the sciences, social sciences and humanities substantiates that at this level of aggregation there is no need for any revision of national indicators and the underlying journal citation measures in the context of excluding self-citations. This revised version was published online in June 2006 with corrections to the Cover Date.     

The citation impact of social sciences and humanities upon patentable technology

This paper examines the citation impact of papers published in scientific-scholarly journals upon patentable technology, as reflected in examiner- or inventor-given references in granted patents. It analyses data created by SCImago Research Group, linking PATSTAT’s scientific non-patent references (SNPRs) to source documents indexed in Scopus. The frequency of patent citations to journal papers is calculated per discipline, year, institutional sector, journal subject category, and for “top” journals. PATSTAT/Scopus-based statistics are compared to those derived from Web of Science/USPTO linkage. A detailed assessment is presented of the technological impact of research publications in social sciences and humanities (SSH). Several subject fields perform well in terms of the number of citations from patents, especially Library and Information Science, Language and Linguistics, Education, and Law, but many of the most cited journals find themselves in the interface between SSH and biomedical or natural sciences. Analyses of the titles of citing patents and cited papers are presented that shed light upon the cognitive content of patent citations. It is proposed to develop more advanced indicators of citation impact of papers upon patents, and ways to combine citation counts with citation content and context analysis.

     

Does self-citation pay?

Self-citations — those where authors cite their own works — account for a significant portion of all citations. These self-references may result from the cumulative nature of individual research, the need for personal gratification, or the value of self-citation as a rhetorical and tactical tool in the struggle for visibility and scientific authority. In this article we examine the incentives that underlie self-citation by studying how authors’ references to their own works affect the citations they receive from others. We report the results of a macro study of more than half a million citations to articles by Norwegian scientists that appeared in the Science Citation Index. We show that the more one cites oneself the more one is cited by other scholars. Controlling for numerous sources of variation in cumulative citations from others, our models suggest that each additional self-citation increases the number of citations from others by about one after one year, and by about three after five years. Moreover, there is no significant penalty for the most frequent self-citers — the effect of self-citation remains positive even for very high rates of self-citation. These results carry important policy implications for the use of citations to evaluate performance and distribute resources in science and they represent new information on the role and impact of self-citations in scientific communication.     

Publication activity, citation impact and bi-directional links between publications and patents in biotechnology

The study focuses on publication activity, citation impact and citation links between publications and patents in biotechnology. The European Union (EU), US, Japan and China are the most important global players. However, the landscape is changing since the EU and the US are losing ground because of challenges from a group of emerging economies. National profiles differ between the two groups of main players and upcoming countries; the focus on red biotechnology in the US and Europe is contrasted by propensity for white and green technology in Asia. Furthermore, the subject profile of biotechnology papers citing patents and cited by patents as well as the relationship between patent citations and citation impact in scientific literature is explored. Papers that cite patents tend to reflect propensity towards white biotechnology while patent-cited publications have a higher relative share in red biotechnology. No significant difference concerning the citation impact of publications ??citing patents?? and ??not citing patents?? can be found. This is contrasted by the observation that patent-cited papers perform distinctly better in terms of standard bibliometric indicators than comparable publications that are not linked to technology in this direction.     

Correlation between quality and quantity in scientific production: A case study of Iranian organizations from 1997 to 2006

In order to prevent the formation of a gap between the quality and quantity in Iranian scientific publications, this study makes an effort to analyze Iranian scientific publications indexed on the ISI Web of Science database using quantitative and qualitative scientometrics criteria over a ten year period. As a first step, all Iranian institutes were divided into three categories; universities, research institutes and other organizations. Then they were compared according to quantitative and qualitative criteria. Second, the correlation between the quality and quantity of the publications was measured. The research findings indicated that, according to qualitative criteria (citation, citation impact and percentage of cited documents) there are no meaningful differences among the three groups, while regarding quantitative criterion(number of papers), universities rank higher than the other two groups. The results also indicated that there is a positive and meaningful correlation among qualitative and quantitative criteria in the scholarly scientific publications conducted by Iranian organizations. In other words, in Iranian organizations the quality of publications increases as their quantity increases. The comparison of magnitude of correlation between these two criteria in the three categories reveals the fact that the correlation between number of papers and citations criterion in research institutes is stronger than the other two groups.     

Use of bibliometric information to assist research policy making. A comparison of publication and citation profiles of Full and Associate Professors at a School of Chemistry in Uruguay

Summary Publication and citation profiles of Full and Associate Professors at the School of Chemistry of the Universidad de la República in Uruguay were investigated. The groups do not exhibit markedly different age averages. However, the average time since they started publishing, as well as other characteristics of their publication records, like productivity or citations, set them apart. From the point of view of both the number of papers per author and per year of activity, on one side, and of the number of citations per year of activity, on the other, the group of Full Professors has statistically significant larger averages than the Associate Professors. The impact of self-citations, multi-authorship and internationalization of the publications were analyzed within the two groups and shown to have no excessive or predictable influence on those parameters, except in the case of few (≤ 2) or many (>8) authors. It is suggested in this paper that these two indicators, number of papers per author per production year and number of citations per production year, combined in a plot allowing a bidimensional ranking of the individuals in the groups, may be used profitably as one of the components in the development of a policy toward promotion of Associate Professors. The analysis showed also that the quotient of citations received to number of papers published, even when derived from actual citation data of the scientists without involving the impact factors of the journals in which they publish, are not good parameters to use for that purpose, essentially because there is a reduction in the information content of the indicator with respect to those described before.     

Does co-authorship inflate the share of self-citations?

In recent papers, the authors have studied basic regularities of author self-citations. The regularities are related to the ageing, to the relation between self-citations and foreign citations and to the interdependence of self-citations with other bibliometric indicators. The effect of multi-authorship on citation impact has been shown in other bibliometric studies, for instance, by Persson et al. (2004). The question arises whether those regularities imply any relation between number of co-authors and the extent of author self-citations. The results of the present paper confirm the common notion of such effects only in part. The authors show that at the macro level multi-authorship does not result in any exaggerate extent of self-citations. This revised version was published online in June 2006 with corrections to the Cover Date.