Comparison of citation and usage indicators: the case of oncology journals
- First Online:
- 397 Downloads
It is the objective of this article to examine in which aspects journal usage data differ from citation data. This comparison is conducted both at journal level and on a paper by paper basis. At journal level, we define a so-called usage impact factor and a usage half-life in analogy to the corresponding Thomson’s citation indicators. The usage data were provided from Science Direct, subject category “oncology”. Citation indicators were obtained from JCR, article citations were retrieved from SCI and Scopus. Our study shows that downloads and citations have different obsolescence patterns. While the average cited half-life was 5.6 years, we computed a mean usage half-life of 1.7 years for the year 2006. We identified a strong correlation between the citation frequencies and the number of downloads for our journal sample. The relationship was lower when performing the analysis on a paper by paper basis because of existing variances in the citation-download-ratio among articles. Also the correlation between the usage impact factor and Thomson’s journal impact factor was “only” moderate because of different obsolescence patterns between downloads and citations.
KeywordsJournal metrics Journal impact factor Usage impact factor Cited half-life Usage half-life
- Armbruster, C. (2007). Access, usage and citation metrics: What function for digital libraries and repositories in research evaluation? Online available at URL: http://www.lub.lu.se/fileadmin/user_upload/pdf/NCSC/ncsc2008_chris_armbruster.pdf (26 November 2008).
- Bollen, J., Van De Sompel, H., Smith, J.A., & Luce, R. (2005). Toward alternative metrics of journal impact: A comparison of download and citation data, online available at URL: http://public.lanl.gov/herbertv/papers/ipm05jb-final.pdf (26 November 2008).
- Chu, H., & Krichel, T. (2007). Downloads vs. citations in economics: Relationships, contributing factors & beyond. In: Proceedings of the 11th International Society for Scientometrics and Informetrics conference, pp. 207–215, Madrid, Spain, June 25–27.Google Scholar
- Darmoni, S. J., Roussel, F., Benichou, J., Thirion, B., & Pinhas, N. (2002). Reading factor: a new bibliometric criterion for managing digital libraries. Journal of the Medical Library Association, 90(3), 323–327.Google Scholar
- Wan, J.-K., Hua, P.-H., Rousseau, R., & Sun, X.-K. (2008). The download immediacy index (DII): Experiences using the CNKI full-text database (in press).Google Scholar