The impact factor rank-order distribution revisited
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There is some controversy around the impact factor (IF) rank-order distribution. The controversy is around the shape of the IF-rank-order distribution. In some articles (Lancho-Barrantes et al. 2010; Guerrero-Bote et al. 2007) one claims examples of convexly decreasing IF-rank-order distributions, while in other contributions the S-shape (first convex, then concave) is advocated (Mansilla et al. 2007; Martinez-Mekler et al. 2009; Campanario 2010a,b; Egghe 2009). Egghe and Waltman (2011) show both shapes.
The difference between the two shapes can be explained through the size-frequency distribution of impact factors. To be as clear as possible we will repeat here the definitions of rank-order distributions and size-frequency distributions. They can be given in a general context of sources and items (Egghe 2005) but since, in this note we are only interested in the journal-IF relation, we will, mainly, use this terminology.
KeywordsGaussian Distribution Visual Inspection Impact Factor Number Theory Inverse Function
- Egghe, L. (2005). Power laws in the information production process: Lotkaian Informetrics. Oxford, UK: Elsevier.Google Scholar
- Egghe, L., & Waltman, L. (2011). Relations between the shape of a size-frequency distribution and the shape of a rank-frequency distribution. Information Processing and Management, to appear.Google Scholar