In addition, by putting less weight on the upper part of the earnings distribution, the Gini index of the logarithm of earnings may yield a country ranking that differs from that of the Gini index. The logarithm of the 90/10 percentile ratio does not have these two weaknesses and is therefore preferred in this article. The main limitation of this measure is that it only builds on the estimated effect of explanatory variables at the 10th and 90th percentiles, and leaves aside effects on the middle class.