A statistical assessment of two measures of citation: The impact factor and the immediacy index

摘要

The dynamics and internal structure of the system of scientific communication are greatly influenced by the varying quality of the primary journals in which scientific information is published. The analysis of citations is among the means by which policy-makers, scientists and librarians seek to achieve a greater understanding of the qualitative forces that affect formal communications in science. This paper reports the findings of an investigation which was conducted in order to determine if either the impact factor or the immediacy index—two derivative measures of citation formulated by Garfield and the Institute for Scientific Information—provide useful insights into the qualitative relations among scientific journals. The results of the investigation, which was concerned with the statistical characteristics of the relationships among the variables forming the basis for the two measures, indicate that the measures are not significant and that the order which either produces among a list of journals is not markedly different than that which is produced when such journals are ranked in terms of uncorrected rates of citation.