Impact of bibliometric studies on the publication behaviour of authors

It has been widely discussed how individuals change the way they act and react in studies just because they are under observation. In this paper, we try to analyse how this so-called Hawthorne effect applies to researchers that are the subject of bibliometric investigations. This encompasses individual assessments as well as international performance comparisons. We test various bibliometric indicators for notable changes in the last decade from a world-wide perspective and deduce explanations for changes from the observations. We then concentrate on the behaviour of German authors in particular, to show national trends. The German publication behaviour is evaluated in regard to citation rates and collaborations in publications and size, publisher country and impact of the journals chosen for publication. We can conclude that authors adapt their publication behaviour to aim for journals that are more internationally known and have a US publisher. Also, a trend from more specialized journals to journals with a broader scope can be observed that raises the question whether the implicit penalization of specialized fields in the bibliometrics leads to undesired shifts in conducted research.