A statistical model for citation processes, a particular version of a non-homogeneous birth process, is analysed in the context
of predictions of future citation rates. Important properties of the process were already studied by the author in earlier
papers. Although the applicability of the model was demonstrated by several examples, practical aspects of predictions and
questions of statistical reliability were not tackled so far. The present study is focused on the demonstration of the possibility
of true predictions and on the analysis of the statistical reliability of predictions based on the mean value functionE(X(t)−X(s)/X(s)=i) of citation processes. The citation rates for papers published in 1980 and 1991 were recorded in the period 1980 through
1995, and 1991 through 1995, respectively, in all science areas. It is shown that parameters of mean value functions estimated
for earlier time periods can be applied to more recent years, too. As a by-product, the model may serve as a validation tool
for the particular choice of citation windows in evaluation studies.
The need for standardisation in bibliometric research and technology is discussed in the context of failing communication within the scientific community, the unsatisfactory impact of bibliometric research outside the community and the observed incompatibility of bibliometric indicators produced by different institutes. The development of bibliometric standards is necessary to improve the reliability of bibliometric results, to guarantee the validity of bibliometric methods and to make bibliometric data compatible. Both conceptual and technical questions are raised. Consequences of lacking standards are illustrated by typical examples. Finally, particular topics of standardisation are proposed based on experiences made at ISSRU.
As a consequence of the dramatic upheaval in East-Europe the German reunification has become one of the central problems of nowadays. Several relevant publications have more or less cautiously forecasted the rise of a new superpower in the midst of Europe. The present study attempts to shed light on some quantitative aspects of the research performance in both parts of Germany. Selected citation based indicators are used to determine the initial position and future of the United Germany in scientific research. Though the reunification involves an essential increase of the scientific potential, the actual indicator values exhort to rather cautious expectations concerning the immediate intensification of research performance.
International scientific collaboration is very sensitive to political and economic changes in a country or a geopolitical region. Collaboration in research is reflected by the corresponding coauthorship of the published results which can be analysed with the help of bibliometric methods. Based on data from theScience Citation Index (SCI), the change of annual international coauthorship patterns ofBulgaria, Czechoslovakia, Hungary, Poland andRomania have been analysed for the periods 1981–1985 and 1984–1993, respectively. It is shown that international collaboration was not developing similarly in the countries under study. Whilst scientific communities of Hungary and Poland have already been opening in the early 80s, the international collaboration of the other East-European countries was still dominated by COMECON relations till 1989. As expected, since 1990 an increasing scientific collaboration with highly developed countries can be observed in all five countries. At the same time, scientific collaboration with the former communist countries shows a clear decline. The great share of international co-authorship links is some countries reflect various tendencies part of which are interpreted with the help of a cardiologic model.
Models and indicators characterizing the dynamics of national publication productivity distributions are presented. The indicator triplet: transience, renewal, and dynamism is used to describe the «physical shape» of a national scientific community.
A theoretical model of repetitive events is presented and applied to the scientific publication process. Based on three simple postulates, a relation between population growth and distribution of authors by publication productivity in a scientific community is established. Predictions of the model are supported by empirical evidences.