Probing the h-core: an investigation of the tail–core ratio for rank distributions
- 291 Downloads
The set of citations received by a set of publications consists of citations received by articles in the h-core and citations received by articles in the h-tail. Denoting the cardinalities of these fours sets as C, P, C H and C T we introduce the tail-core ratio (C T/C H) and show that in practical cases this ratio tends to increase. Introducing further the k-index, defined as k = (C/P)/(C T/C H), we show that this index decreases in most practical cases. A power law model is in accordance with these practical observations.
Keywordsh-Index h-Core h-Tail Tail–core ratio v-Index k-Index
Fred Y. Ye’s work is supported by a grant from the National Natural Science Foundation of China (NSFC Grant No. 70773101), while Ronald Rousseau’s work is supported by the National Natural Science Foundation of China Grant No. 70673019. The authors thank graduate student Jianhui Tang for assistance in data collection and Leo Egghe for checking the power law calculations.
- Egghe, L. (2005). Power laws in the information production process: Lotkaian informetrics. Amsterdam: Elsevier.Google Scholar
- Egghe, L. (2010). The Hirsch-index and related impact measures. Annual Review of Information Science and Technology (to appear).Google Scholar
- Liang, L. M., & Rousseau, R. (2009). A general approach to citation analysis and an h-index based on the standard impact factor framework. In B. Larsen & J. Leta (Eds.), ISSI 2009; 12th international conference on scientometrics and informetrics (pp. 143–153). Rio de Janeiro: BIREME and University of Rio de Janeiro.Google Scholar
- Rousseau, R. (2006). New developments related to the Hirsch index. Science Focus, 1(4), 23–25 (in Chinese). English version available at: E-LIS: code 6376.Google Scholar