The first dimension is the average income level of those in the society with the most disadvantaged circumstances, and the second dimension is the degree to which total income inequality is due to differential effort, as opposed to differential circumstances. This pair of numbers is computed for a set of 22 European countries. No country dominates all others on both dimensions. The two-dimensional measure induces a partial ordering of countries with respect to development.
Suppose we are concerned with the inequalities that exist in a society with respect to the distribution of some desirable good or advantage – wealth, life expectancy, literacy, or wage-earning capacity. The causes of inequality in that distribution can be partitioned into two categories: those for which individuals should not be held responsible, and those for which they should be. We need not here be concerned with the problem of free will, and the possibility that people are not responsible for anything if they lack free will, because every society has a conception of responsibility, and we may take that as the politically salient conception. Thus, in many societies, it is thought wrong that an individual’s income be strongly correlated with her parent’s education or social position, for, assuming that that correlation reflects causality, these family characteristics seem to be ones from which children should not differentially benefit or suffer. On the other hand, most societies believe that adults should be held responsible for various choices that they make, assuming that they possess adequate information about the alternatives. Let us call the social and biological aspects of a person’s environment for which society believes he should not be responsible his circumstances, those choices and actions for which he should be held responsible, his effort, and the desirable good whose distribution we are concerned with the objective.