Abstract
The bibliometric phenomena often produce highly skewed distributions where most of the items (e.g.articles)are"concentrated"in a small population of sources(e.g.authors), while the remaining items are spread out over the rest of the population. Many measures for measuring "concentration"have been proposed, nevertheless the notion of concentration is not clear. In this paper I would like to review the notion of concentration from the two viewpoints, i.e., absolute concentration and relative concentration. Linking the two viewpoints with the geometric expression of the Lorenz curve, I analyze the characteristics of concentration measures through the simulations using the geometric expression.
