Albarrán et al (2009a) introduced a novel methodology for the evaluation of citation distributions using a pair of high- and low-impact measures defined over the set of articles with citations below or above a critical citation level. Albarrán et al (2009b) presented the first empirical applications to a situation in which the world citation distribution in 22 scientific fields is partitioned into three geographical areas: the USA, the European Union, and the rest of the world. In this paper, we find that cardinal differences between the results obtained with our high-impact index and the mean citation rate are of a large order of magnitude. When, in addition, the percentage in the top 5% of most cited articles or the percentage of uncited articles are used, there are still important quantitative differences with respect to the high- and low-impact indicators advocated in our approach. Copyright , Beech Tree Publishing.