Thus to judge the inequality of a society, it is not enough to observe that some individuals earn very high incomes. For example, to say that the “income scale goes from 1 to 10” or even “1 to 100” does not actually tell us very much. We also need to know how many people earn the incomes at each level. The share of income (or wealth) going to the top decile or centile is a useful index for judging how unequal a society is, because it reflects not just the existence of extremely high incomes or extremely large fortunes but also the number of individuals who enjoy such rewards.
