A scientometrics law about co-authors and their ranking: the co-author core

Rather than “measuring” a scientist impact through the number of citations which his/her published work can have generated, isn’t it more appropriate to consider his/her value through his/her scientific network performance illustrated by his/her co-author role, thus focussing on his/her joint publications, and their impact through citations? Whence, on one hand, this paper very briefly examines bibliometric laws, like the h-index and subsequent debate about co-authorship effects, but on the other hand, proposes a measure of collaborative work through a new index. Based on data about the publication output of a specific research group, a new bibliometric law is found. Let a co-author C have written J (joint) publications with one or several colleagues. Rank all the co-authors of that individual according to their number of joint publications, giving a rank r to each co-author, starting with r = 1 for the most prolific. It is empirically found that a very simple relationship holds between the number of joint publications J by coauthors and their rank of importance, i.e., J ∝ 1/r. Thereafter, in the same spirit as for the Hirsch core, one can define a “co-author core”, and introduce indices operating on an author. It is emphasized that the new index has a quite different (philosophical) perspective that the h-index. In the present case, one focusses on “relevant” persons rather than on “relevant” publications. Although the numerical discussion is based on one “main author” case, and two “control” cases, there is little doubt that the law can be verified in many other situations. Therefore, variants and generalizations could be later produced in order to quantify co-author roles, in a temporary or long lasting stable team(s), and lead to criteria about funding, career measurements or even induce career strategies.     

Two simple new bibliometric indexes to better evaluate research in disciplines where publications typically receive less citations

The paper proposes two simple new indexes—k and w—to assess a scientist’s publications record based on citations. The two indexes are superior to the widely used h index (Hirsch, 2005), as they preserve all its valuable characteristics and try to overcome one of its shortcomings, i.e. that it uses only a fraction of the information contained in a scientist’s citations profile and, as a result, it is defined over the set of positive integers and does not show a sufficiently fine ‘granularity’ to allow a fully satisfactory ranking of scientists. This problem is particularly acute in many areas of Social Sciences and Humanities, where scientific productivity and citation practices typically yield fewer citations per paper and, as a consequence, are characterized by ‘structurally’ lower values of the h index. Both the indexes proposed are defined over R⁺, their integer part is equal to the scientist’s h index and they fall in the right-open interval [h, h+1). While the h index is influenced only by part of the citations received by a scientist’s most-cited publications, the k index takes into account all the citations received by her most-cited publications and the w index accounts for the citations received by the entire set of her publications. Variants of the k and w indexes are proposed which consider co-authorship. To show the extent to which the h index and the new indexes proposed may yield different results, they are calculated for 332 professors of economics in Italian universities and the results obtained used to rank Italian university departments.     

Visualizing the context of citations referencing papers published by Eugene Garfield: a new type of keyword co-occurrence analysis

During Eugene Garfield’s (EG’s) lengthy career as information scientist, he published about 1500 papers. In this study, we use the impressive oeuvre of EG to introduce a new type of bibliometric networks: keyword co-occurrences networks based on the context of citations, which are referenced in a certain paper set (here: the papers published by EG). The citation context is defined by the words which are located around a specific citation. We retrieved the citation context from Microsoft Academic. To interpret and compare the results of the new network type, we generated two further networks: co-occurrence networks which are based on title and abstract keywords from (1) EG’s papers and (2) the papers citing EG’s publications. The comparison of the three networks suggests that papers of EG and citation contexts of papers citing EG are semantically more closely related to each other than to titles and abstracts of papers citing EG. This result accords with the use of citations in research evaluation that is based on the premise that citations reflect the cognitive influence of the cited on the citing publication.     

Analysis of bibliometric indicators for individual scholars in a large data set

Citation numbers and other quantities derived from bibliographic databases are becoming standard tools for the assessment of productivity and impact of research activities. Though widely used, still their statistical properties have not been well established so far. This is especially true in the case of bibliometric indicators aimed at the evaluation of individual scholars, because large-scale data sets are typically difficult to be retrieved. Here, we take advantage of a recently introduced large bibliographic data set, Google Scholar Citations, which collects the entire publication record of individual scholars. We analyze the scientific profile of more than 30,000 researchers, and study the relation between the h-index, the number of publications and the number of citations of individual scientists. While the number of publications of a scientist has a rather weak relation with his/her h-index, we find that the h-index of a scientist is strongly correlated with the number of citations that she/he has received so that the number of citations can be effectively be used as a proxy of the h-index. Allowing for the h-index to depend on both the number of citations and the number of publications, we find only a minor improvement.     

The utility of scientific papers

This article investigates the function of scientific papers in the production of scientific knowledge. For this production, the citations made of these papers in the scientific literature can be considered as economic utilities. The work of the scientist is described as the production of citations by means of citations. The number of citations received by a given paper can be used to measure the paper's formal utility. The formal utility of scientific papers is studied empirically. It is concluded that the references contained in a scientific paper are a major determinant of its future utility.     

Dentistry scientometric analysis: a comparative study between Brazil and other most productive countries in the area

This research aims at performing a comparative study between the Brazilian scientific production in Dentistry, from 2000 to 2009 and countries that contribute with at least 2 % of the world’s scientific production indexed in the Scopus database. More specifically, we intend to assess the annual Brazilian scientific production by comparing it to the other countries’, analyze the Brazilian and other countries’ publications in journals with higher impact factors, as well as to highlight the scientific production from these countries and its international visibility, measured by its total and by its average of citations and normalized citation index per year, by comparing the countries, and to compare the index h of such countries. As work procedure, the SCImago Journal and Country Rank was used as source, identifying the group of producing countries in the Dentistry area from 1996 to 2009. From a total of 136 countries, 13 were highlighted as the most productive, each one of them accounting for at least 2 % the worldwide scientific production in the area. The following indicators were raised for each country: number of produced documents, total of citations, self-citations, average of citations per document and index h. We verified that Brazil is the only country in Latin America that is pictured among the most productive ones in the Dentistry area. We observed that Brazil presents a growing visibility and impact in the international scenery, what suggests that its production is constantly consolidating, with Brazilian scientific recognition in the main vehicles of dissemination in the area.     

Correlations between bibliometrics and peer evaluation for all disciplines: the evaluation of Brazilian scientists

This paper correlates the peer evaluations performed in late 2009 by the disciplinary committees of CNPq (a Brazilian funding agency) with some standard bibliometric measures for 55 scientific areas. We compared the decisions to increase, maintain or decrease a scientist’s research scholarship funded by CNPq. We analyzed these decisions for 2,663 Brazilian scientists and computed their correlations (Spearman rho) with 21 different measures, among them: total production, production in the last 5 years, production indexed in Web of Science and Scopus, total citations received (according to WOS, Scopus, and Google Scholar), h-index and m-quotient (according to the three citation services). The highest correlations for each area range from 0.95 to 0.29, although there are areas with no significantly positive correlation with any of the metrics.     

Measuring co-authors’ contribution to an article’s visibility

The visibility of an article depends to a large extent on its authors. We study the question how each co-author’s relative contribution to the visibility of the article can be determined and quantified using an indicator, referring to such an indicator as a CAV-indicator. A two-step procedure is elaborated, whereby one first chooses an indicator (e.g. total number of citations, h-index …) and subsequently one of two possible approaches. The case where the indicator is an h-type index is elaborated in a Lotkaian framework. Different examples illustrate the procedure and the choices involved in determining a CAV-indicator.     

The conundrum of research productivity: a study on sociologists in Italy

This paper aims to understand the influence of institutional and organisational embeddedness on research productivity of Italian sociologists. We looked at all records published by Italian sociologists in Scopus from 1973 to 2016 and reconstructed their co-authorship patterns. We built an individual productivity index by considering the number and type of records, the impact factor of journals in which these records were published and each record’s citations. We found that sociologists who co-authored more frequently with international authors were more productive and that having a stable group of co-authors had a positive effect on the number of publications but not on citations. We found that organisational embeddedness has a positive effect on productivity at the group level (i.e., sociologists working in the same institute), less at the individual level. We did not found any effect of the scientific disciplinary sectors, which are extremely influential administratively and politically for promotion and career in Italy. With all caveats due to several limitations of our analysis, our findings suggest that internationalisation and certain context-specific organisational settings could promote scientist productivity .     

Soil science and the <Emphasis Type="Italic">h</Emphasis> index

Soil science is a relatively young and specialised field of science. This note discusses the use of the h index as a scientific output measure in soil science. We explore the governing factors of h index in soil science: the number of soil scientists, the number of papers published, the average number of citations, and the age of the scientist. We found the average relationship between h index and scientific age for soil science: h = 0.7 t. The h index for soil science is smaller than other major science disciplines but norms for h need to be established     

Quantifying scientific collaboration impact by exploiting collaboration-citation network

Despite the growing interest in exploring the collaboration patterns and the structure of collaboration networks, the impact of collaboration associated with time-varying scholarly networks is hardly known. This paper investigates collaboration and productivity in a science career and quantifies the impact of collaboration in the collaboration-citation network. Moreover, this paper also investigates collaboration patterns and examines the typical duration of research collaborations. A SCIRank model is proposed to quantify the impact of scientific collaboration, which not only reveals the impact of co-author pairs but also identifies scholarly papers with the outstanding impact that leads to Nobel Prize awards.

     

Disciplinary determinants of bibliometric impact in Danish industrial research: Collaboration and visibility

Firms are increasingly dependent on networks and network visibility for innovation. Bibliometric impact can be regarded as a measure of a firm's visibility in knowledge-producing networks and may explain why companies publish their results. However, this visibility varies across disciplines. This paper examines publications produced by Danish companies in 1996, 1998 and 2000 to show how citation and collaboration patterns relate in different disciplines. The main findings are that for disciplines characterized by international collaboration and many authors per paper, international collaboration results in a greater number of citations. National collaboration does not, however, seem to make any difference to citation impact in industrial research. In disciplines where multinational collaboration and multi-authorship is uncommon, no clear picture of impact patterns can be obtained. By extension, this research may provide knowledge on how citations of papers in scientific journals can be used as a potential window to scientific networks for firms. This revised version was published online in June 2006 with corrections to the Cover Date.     

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 productivity in soil science in the Philippines

Understanding the direction and magnitude of soil science publication in the Philippines is crucial in formulating research priorities and funding allocation. There is no consensus on the current state of soil science publication in the Philippines, thus this study was conducted to elucidate the trend in the soil science publication. We conducted an in-depth analysis on the total number of publications and the total number of citations of soil science publications collected from Thomson ISI database. Results revealed an upsurge in soil science publication from 1970 to 2000 with no indication that this trend is slowing down. Increases in the number of citations with time are consistent with increases in the total number of publications (r = 0.93; p < 0.05). Results further revealed that the soil science publication in the Philippines is biased towards rice research particularly soil water with very few studies were published for plant nutrition and soil chemistry. The present study highlights the need for a paradigm shift in soil science research from mostly rice related research to environmental research. Ways to increase soil science publication among Filipino soil scientist’s particularly in academic institutions is proposed. Finally, since only a few government-funded research have been published, future studies should stress on identifying factors that influence scientific productivity of most soil scientists in the Philippines.     

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.     

Are academics who publish more also more cited? Individual determinants of publication and citation records

Thanks to a unique individual dataset of French academics in economics, we explain individual publication and citation records by gender and age, co-authorship patterns (average number of authors per article and size of the co-author network) and specialisation choices (percentage of output in each JEL code). The analysis is performed on both EconLit publication scores (adjusted for journal quality) and Google Scholar citation indexes, which allows us to present a broad picture of knowledge diffusion in economics. Citations are largely driven by publication records, which means that these two measures are partly substitutes, but citations are also substantially increased by larger research team size and co-author networks.     

#Psychology: a bibliometric analysis of psychological literature in the online media

Online media and especially social media are becoming more and more relevant to our everyday life. Reflecting this tendency in the scientific community, alternative metrics for measuring scholarly impact on the web are increasingly proposed, extending (or even replacing) traditional metrics (e.g., citations, journal impact factor, etc.). This paper explores the relationship between traditional metrics and alternative metrics for psychological research in the years from 2010 to 2012. Traditional publication metrics (e.g., number of citations, impact factor) and alternative metrics (collected from Altmetric, a website that collects and counts references as they appear in Wikipedia, public policy documents, research blogs, mainstream media, or social networks) were extracted and compared, using a dataset of over 245,000 publications from the Web of Science. Results show positive, small to medium, correlations on the level of individual publications, and frequently medium to high correlations on the level of research fields of Psychology. The more accumulated the level of analysis, the higher the correlations. These findings are fairly robust over time and comparable to findings from research areas other than Psychology. Additionally, a new metric, the Score Factor, is proposed as a useful alternative metric to assess a journal’s impact in the online media.     

The iCE approach for journal evaluation

Recent research has shown that simple graphical representations of research performance can be obtained using two-dimensional maps based on impact (i) and citations (C). The product of impact and citations leads to an energy term (E). Indeed, using E as the third coordinate, three-dimensional landscape maps can be prepared. In this paper, instead of using the traditional impact factor and total citations received for journal evaluation, Article Influence^TM and Eigenfactor^TM are used as substitutes. Article Influence becomes a measure of quality (i.e. a proxy for impact factor) and Eigenfactor is a proxy for size/quantity (like citations) and taken together, the product is an energy-like term. This can be used to measure the influence/prestige of a journal. It is also possible to propose a p-factor (where p = E ^1/3) as an alternative measure of the prestige or prominence of a journal which plays the equivalent role of the h-index.