The literature on the measurement of inequalities in health has drawn on the development
of rank-dependent measures in the income inequality literature. A long-standing issue in the
literature on health inequality is whether all inequalities ought to be measured or only those,
which show some systematic association with indicators of socioeconomic status (Gakidou et al.,
2000; Wagstaff, 2001). Some of the earlier contributions by economists (e.g. Le Grand, 1989)
used Lorenz curves and the Gini index to measure inequality in mortality rates. A Lorenz curve
describes the cumulative distribution of health in a population ranked by health and the Gini index,
henceforth denoted as G, measures the deviation from an equal distribution as (twice) the area
between the Lorenz curve and the diagonal.