The highly cited papers of professors as an indicator of a research group's scientific performance

In the first part of the paper the citations in 1986 and 1987 of 3938 papers published in 1985 by 324 research groups in the faculties of science and of medicine of eight universities in the Netherlands are analyzed. Because of the large statistical spread of (1) the number of short-term citations of papers cited equally frequently over a long period, and (2) the number of citations over a long period of papers by the same author, short-term citation scores appear to be an unreliable indicator of a research group's contribution to science. In the second part of the paper an alternative approach is presented, based on a subdivision of the 3938 papers in papers authored by professors with 0–2, 3–8, or ≥9 highly cited papers (HCPs, ≥25 citations) to their name. Very large citation score differences were found for the three categories. For example: for papers first-authored by a professor, the average number of citations per person in 1986 and 1987 for 1985 papers was for 161 professors with ≥9 HCPs a factor 14 larger than for 575 professors with only 0–2 HCPs; for papers co-authored by professors, this factor was 6.6. These findings justify the conclusion that the number of HCPs scored by the professors (and other senior scientists) during their entire career is a much more reliable predictor of the performance of a research group than the number of short-term citations of the articles published by the group within a short period. A research group's contribution to science is primarily determined by the individual scientifictalents of its members.