Bibliometric statistical properties of the 100 largest European universities: prevalent scaling rules in the science system

TL;DR

This study analyzes bibliometric indicators of the 100 largest European universities, revealing size-dependent scaling laws, performance patterns, and citation behaviors that suggest prevalent systemic properties in scientific research output.

Contribution

It uncovers size-dependent scaling rules and performance patterns in university bibliometrics, extending previous findings at the research group level to large universities.

Findings

Size-dependent cumulative advantage in citations for universities.

Lower-performance universities benefit more from size in citation counts.

Higher journal impact correlates with fewer not-cited publications.

Abstract

For the 100 largest European universities we studied the statistical properties of bibliometric indicators related to research performance, field citation density and journal impact. We find a size-dependent cumulative advantage for the impact of universities in terms of total number of citations. In previous work a similar scaling rule was found at the level of research groups. Therefore we conjecture that this scaling rule is a prevalent property of the science system. We observe that lower performance universities have a larger size-dependent cumulative advantage for receiving citations than top-performance universities. We also find that for the lower-performance universities the fraction of not-cited publications decreases considerably with size. Generally, the higher the average journal impact of the publications of a university, the lower the number of not-cited publications. We find that the average research performance does not dilute with size. Large top-performance universities succeed in keeping a high performance over a broad range of activities. This most probably is an indication of their scientific attractive power. Next we find that particularly for the lower-performance universities the field citation density provides a strong cumulative advantage in citations per publication. The relation between number of citations and field citation density found in this study can be considered as a second basic scaling rule of the science system. Top-performance universities publish in journals with significantly higher journal impact as compared to the lower performance universities. We find a significant decrease of the fraction of self-citations with increasing research performance, average field citation density, and average journal impact.