Johannes Stegmann

Hypothesis generation guided by co-word clustering

Co-word analysis was applied to keywords assigned to MEDLINE documents contained in sets of complementary but disjoint literatures. In strategical diagrams of disjoint literatures, based on internal density and external centrality of keyword-containing clusters, intermediate terms (linking the disjoint partners) were found in regions of below-median centrality and density. Terms representing the disjoint literature themes were found in close vicinity in strategical diagrams of intermediate literatures. Based on centrality-density ratios, characteristic values were found which allow a rapid identification of clusters containing possible intermediate and disjoint partner terms. Applied to the already investigated disjoint pairs Raynauds Disease - Fish Oil, Migraine - Magnesium, the method readily detected known and unknown (but relevant) intermediate and disjoint partner terms. Application of the method to the literature on Prions led to Manganese as possible disjoint partner term. It is concluded that co-word clustering is a powerful method for literature-based hypothesis generation and knowledge discovery.

Building a List of Journals with Constructed Impact Factors.

This communication describes the building of a list of constructed impact factors (CIF) for biomedical journals not included in the 1996 editions of the Journal Citation Reports (JCR). The online retrieval from the host DIMDI of the data needed for impact factor calculation is described in detail. At present, the CIF list comprises 338 titles. The top 100 (ranked according to their CIFs) are shown. The complete list is available via the World Wide Web at the URL: http://www.medizin.fu‐berlin.de/medbib/CIF/cif.html. The possible usefulness of constructed impact factors for citation and evaluation studies is discussed.

Research evaluation. Part I: productivity and citedness of a German medical research institution

An evaluation exercise was performed involving 313 papers of research staff (66 persons) of the Deutsche Rheuma-Forschungszentrum (DRFZ) published in 2004–2008. The records and citations to them were retrieved from the Web of Science (Thomson Reuters) in March 2010. The authors compared productivity and citedness of “group leaders” vs. “regular scientists”, of “male scientists” vs. “female scientists” using citation-based indexes. It was found that “group leaders” are more prolific and cited more often than “regular scientists”, the same is true considering “male” vs. “female scientists”. The greatest contrast is observed between “female leaders” and “female regular scientists”. The above mentioned differences are significant in indexes related to the number of papers, while values of indexes characterizing the quality of papers (average citation rate per paper and similar indexes) are not substantially different among the groups compared. The mean value of percentile rank index for all the 313 papers is 58.5, which is significantly higher than the global mean value of about 50. This fact is evidence of a higher citation status, on average, of the publications from the DRFZ.

Erratum to: Research evaluation. Part II: gender effects of evaluation: are men more productive and more cited than women?

Productivity and citedness of the staff of a German medical research institution are analyzed. It was found in our previous study (Pudovkin et al.: Scientometrics, doi:10.1007/s11192-012-0659-z, 2012) that male scientists are more prolific and cited more often than female scientists. We explain in our present study one of the possible causes for obtaining this result with reference to Abramo et al. (Scientometrics 84(3): 821–833, 2009), who found in the small subgroups of star scientists a higher performance of male star scientists with respect to female star scientists; but in the remaining complementary subpopulations the performance gap between the two sexes is marginal. In agreement with Abramo et al. (2009), in our small subgroup of star scientists a higher performance of male star scientists with respect to female star scientists could be found. Contrasting, in the large complementary subgroup even a slightly higher performance of female scientists with respect to male scientists was identified. The last is even stronger expressed in favor of women than Abramo’s result that the performance gap between the two sexes is truly marginal. In addition to Abramo et al. (2009), we already found in our previous study, special indexes characterizing the quality of papers (but not quantity) are not substantially different among sexes compared.

Growth and Structure Formation of Collaboration Patterns Obtained from the Journals PNAS, SCIENCE and the Journal of Experimental Medicine

The paper is focused on social network analysis (SNA) and special structure formation processes of collaboration patterns in scientific networks. Three-dimensional visualization is used to show the growth and structural changes over time in the journals PNAS, Journal of Experimental Medicine and SCIENCE. Self-organization occurs in a variety of complex systems in nature and social networks. We will show this process of self-organization can be found also in co-authorship networks.

German medical faculties in the 1990s: on-line bibliometric analysis

Data of publication output from 1993 to 2001 and of observed citation impact relating to citing years 1995 to 1999 were retrieved on-line from the German host DIMDI. Expected citation data (for 1995 to 2002) were calculated using the journal impact factors supplied by ISIs Journal Citation Reports (JCR). For journals not included in the JCR, impact factors were constructed according to the number of citations received from journals indexed in ISI databases. Copyright , Beech Tree Publishing.

Ranganathan Today: A Citation Study

Using citation analysis we investigated the presence of S. R. Ranganathans work in the modern scientific literature. We found that during the past twenty two years nearly 400 papers cite at least one piece of Ranganathans work, significantly more than in the preceding forty years. There is much evidence for a sustainable pervasion of modern science by Ranganathans work and ideas.