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Bibliometrics is a science that uses mathematical and statistical methods to make precise statements about publication behaviour. For example, the so-called journal impact factor provides a good indication of the influence and reputation of a particular journal. A person-related analysis is possible, for example, by determining the so-called h-index. We will gladly help you and show you where you can find these values.

Bibliometric analyses can be useful if one...

... is working on a specific research topic and would like to find out which publications have already appeared on it;

... would like to know which topics are currently being discussed and how much is being published in which field;

... has a research idea and wants to identify suitable co-operation partners and existing networks for the research project;

... is planning to publish an article and would like to know which is the most suitable journal for this;

... wants to determine the research output of an institute or research organisation and compare it with other institutions;

... would like to find out how to increase the perception and visibility of your own research within the specialised community;

... would like to apply for a job, for example, and wants to determine personal key figures in advance.

Bibliometrics analyses scientific publications and their citations using quantitative methods. The instruments used are counting and analysing the various aspects of scientific communication in written form in order to quantify scientific output. Bibliometric analyses are used to compare the publication output of individual scientists, research groups and institutions. They are increasingly being used as an instrument in science management, for example to recognise research trends or to allocate funding on the basis of performance. On the one hand, this requires a careful selection of the data basis and procedures and, on the other, an interpretation of the results that takes several indicators into account. The different understanding of research in the respective subject areas must also be considered in the analysis.

The basic indicators for bibliometric analyses are the number of publications and citations, from which the average number of citations (citation rate) of the articles under consideration can be determined. However, different publication and citation habits in the individual subject areas only allow a direct comparison of the figures within a subject and are also dependent on the database used. Criteria must be defined for further analyses. Depending on the research question, journal- or author-related key figures can be determined.

The so-called journal impact factor expresses how often an article in a journal is cited on average. It is calculated from the number of citations of a journal's articles in the year under review in relation to the number of these articles in the two preceding years. This value is influenced by the different citation habits in the subject areas and by journal-related factors such as article type, journal format, title changes or restrictions on citations by the editors of a journal.

In 2005, physicist Jorge E. Hirsch developed the h-index (or Hirsch number) as an alternative to the journal impact factor. It corresponds to a number h of publications by an author with h or more citations. It is based on a list of the author's publications, sorted by the number of citations in descending order. The advantages of this factor are the independence of high citation numbers of individual publications and the attenuation of the so-called Matthew effect (frequent citation of well-known authors who become even better known as a result). However, the h-index is dependent on the number of publications by the author, which results in advantages for scientists who work continuously, as the robust factor increases in proportion to the duration of professional activity. Originally developed as a factor for comparing authors, an h-index can also be determined for other categories such as journals or topics. However, it is not transferable to working groups.

Licensed by the University Library:

  • The multidisciplinary abstract and citation database Scopus comprises the bibliographic details and abstracts of approx. 87 million articles from over 25,000 titles from 7,000 international publishers, including 23,500 peer-reviewed journals, as well as details of high-quality peer-reviewed Internet sources from all subject areas. Scopus also provides the citations of the scientific articles (references and citations), which can be used as a database for a citation analysis (Who cites whom? Who is cited by whom?). In addition to extensive search options, it is also possible to create your own search profiles and make use of an alert service. Scopus also offers numerous tools for analysing and graphically processing the data.

Freely accessible resources:

  • SCImago Journal & Country Rank contains bibliometric key figures for ranking scientific journals based on the Scopus database.
  • Google Scholar enables a general search for scientific literature and also displays citation data for the results found. Due to the way it works as a web crawler (also known as a spider, searchbot or robot), however, the key figures provided are not reliably reproducible and should therefore be viewed critically when analysing them.

With the constantly growing number of electronic publications, new metrics based on usage figures are also increasingly developing as an important evaluation criterion. In contrast to the classic citation-based metrics, usage statistics and access figures reflect the current scientific significance of a digital document in the scientific community. Article-related metrics such as downloads, views and clicks or mentions of scientific publications in social networks (blogs/Twitter/Facebook) and reference management platforms as well as links saved in Mendeley or CiteULike are recorded.

The informative value of bibliometrics is limited, as the complexity of scientific output and its quality are difficult to depict using key figures. For this reason, several indicators must be taken into account in bibliometric analyses, which should ideally be determined and defined on a subject-specific basis and in consultation with the researchers. Although the number of publications (scientific output) provides a quick overview of the productivity of a person or institution, it cannot provide any information about the quality of research performance. Those who publish a lot do not automatically publish good work. The quality of a paper is reflected in its ‘weight’, i.e. in its information content and its significance for the respective subject. This can neither be represented by figures nor by the level of the journal impact factor.


Dr. Cornelia Bögel
Dr. Cornelia Bögel
Room ZB 222c
Innstraße 29
Phone: +49(0)851/509-1637
Michael Zweier
Michael Zweier
Room ZB 315
Innstraße 29
Phone: +49(0)851/509-1604


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