Does the normalized citation impact of universities profit from certain properties of their published documents - such as the number of authors and the impact factor of the publishing journals? A multilevel modeling approach

Research evaluation based on bibliometrics is prevalent in modern science. However, the usefulness of citation counts for measuring research impact has been questioned for many years. Empirical studies have demonstrated that the probability of being cited might depend on many factors that are not related to the accepted conventions of scholarly publishing. The current study investigates the relationship between the performance of universities in terms of field-normalized citation impact (NCS) and four factors (FICs) with possible influences on the citation impact of single papers: journal impact factor (JIF), number of pages, number of authors, and number of cited references. The study is based on articles and reviews published by 49 German universities in 2000, 2005 and 2010. Multilevel regression models have been estimated, since multiple levels of data have been analyzed which are on the single paper and university level. The results point to weak relationships between NCSs and number of authors, number of cited references, number of pages, and JIF. Thus, the results demonstrate that there are similar effects of all FICs on NCSs in universities with high or low NCSs. Although other studies revealed that FICs might be effective on the single paper level, the results of this study demonstrate that they are not effective on the aggregated level (i.e., on the institutional NCSs level). (C) 2018 Elsevier Ltd. All rights reserved.