Figure 2 .

Skewness of citation. When papers are ranked according to citation order along the abscissa and plotted against the number of citations along the ordinate (both in percentages), the skewness of citation becomes obvious. It concerns 63 sets of original papers (n=1886) as published between 1992 and 2000 by Cardiovascular Research and analysed for citations between 1992 and 2002. About 14% of papers obtain 50% of citations. The most frequently cited 50% of papers obtain about 90% of all citations. Only 66% of papers are cited in a given year, leaving 34% uncited. Obviously, the impact factor of a journal cannot be regarded as a ‘totum pro parte’ for individual papers, although this is done by many academic institutions. Compiled from reference 10.