Imbalances of the Impact Factor
Ziemann and Oestmann showed that the impact factor of medical publications resulting from doctoral theses at the Charité University Hospital rose by 50% over a decade (4). Mooreover, the number of publications per doctoral candidate rose from 0.8 to 1.4.. These data have to be appreciated. Nevertheless, they should also prompt a discussion about the validity of the impact factor in comparison within faculties.
- Submitted manuscripts are carefully reviewed by editors/publishers and peer reviewers in order to determine a priority for publication. As a rule, suggestions are implemented aiming for improving the quality of the presentation and thus citations of the publication (1). In view of the current discussions on plagiarism, these hidden “external services” by reviewers that have not been involved in the study are not trivial.
- The impact factor of medical journals correlates with the number of journals publishing in this domain and the seize of the audience; this results in differences in cross-sectional fields, organ specialties, and subspecialties (2). This is facilitated by modern technologies and several scientific on-line services. Furthermore, formal rules are relevant for citation numbers (1).
- In general, excellent studies with a presumed scientific and medical impact are preferably published in top journals that do not belong to any particular medical specialty. As a result, the impact factor of journals publishing in a specific domain does not necessarily reflect the scientific potential of that specialty. This statement can be illustrated by current experience in pediatric oncology and hematology. In 2012, five researchers recently received prizes and honors, while their corresponding publications were all published in non-pediatric journals (3).
The allocation by specialty for each individual publication is hardly able to abolish such imbalances (2) and appears unrealistic. However, a score that assigns points for the quartile-ranking of a journal within a discipline-specific list is easy to perform and should be considered. If such a score were used across disciplines to compare scientific achievements, the top journal still would retain their influence – however outside of discipline specific lists. Formal biases could be marginalized and disciplines that are currently at a disadvantage could win. This would then enable a valid comparison both within medical faculties and between faculties with different profiles.
em. Prof. Dr. med. Ulrich Göbel
Koordinierungszentrum für Klinische Studien
Universitätsklinikum der Heinrich-Heine-Universität Düsseldorf
Prof. Dr. med. Ludwig Gortner
Klinik für Allgemeine Pädiatrie und Neonatologie
Kliniken Kinder und Jugendmedizin
Universitätsklinikum des Saarlandes
Conflict of interest statement
The authors declare that no conflict of interest exists.
|1.||Göbel U, Gortner L: Peer Review, Impact Factor und Leserpräferenz geben Hinweise zur Erstellung von Publikationen für die klinische Behandlung. Klin Padiatr 2012; 224: 3–7. CrossRef MEDLINE|
|2.||Göbel U, Niem V: Rating und Ranking medizinischer Zeitschriften: Randomisiert kontrollierte Evaluation von Impact Factor und Zahl der gelisteten Journale. Klin Padiatr 2012; 224: 43–50. CrossRef MEDLINE|
|3.||Klingebiel T: Herausragende Wissenschaftspreise und Ehrungen für pädiatrische Onkologen. Klin Padiatr 2012; 224: 121–3. CrossRef MEDLINE|
|4.||Ziemann E, Oestmann J-W: Publications by doctoral candidates at charité university hospital, Berlin, from 1998–2008. Dtsch Arztebl Int 2012; 109(18): 333–7. VOLLTEXT|