The scope of health inequality is summarized using a wide range of metrics. The Concentration Index and the Gini Coefficient, taken from the study of economic inequality and adapted to the study of health inequities, are two specialized indicators.
The Lorenz Curve and the Gini Coefficient #
The Lorenz curve is a well know cumulative frequency curve that contrasts the distribution of a particular variable with the uniform distribution that symbolizes equality and is the foundation for the Gini coefficient. In the present note, we will primarily focus on Concentration Curve and Index.
Concentration Curve and Index #
Income inequality is charted on a Lorentz curve, which compares the total number of people in a given population to their total income. Similarly, the concentration curve may be used to measure the extent to which disparities in each health characteristic are connected to a person’s wealth. In recent years, one has seen a dramatic increase in the concentration curves and index’s application in depicting socioeconomic and health disparities, specifically after the covid pandemic.
Concentration curves may be used to determine if the socioeconomic disparity in a certain health sector variable exists and whether it is more apparent at some time or in some countries than others. A concentration curve, however, does not provide a straightforward way to compare the degree of disparity. The degree of socioeconomic linked disparity in a health variable is quantified by the concentration index (Kakwani 1977, 1980), which is directly connected to the concentration curve
This concentration curve shows the cumulative percentage of the sample arranged by living standards on the x-axis and the corresponding cumulative percentage of the given health variable on the y-axis. The concentration index is defined in terms of the concentration curve, just as the Gini index is defined in the Lorentz curve. The concentration index is calculated as the area between the concentration curve and the line of equality. The concentration index follows the same formula as the Gini coefficient but has a wider range (between -1 and +1) than the latter. The relative degree of concentration among richer or poorer groups is expressed by magnitude.
Further, when health is more common among wealthy groups, the standard concentration index is positive; if not, it is negative. In simple terms, when the health variable’s distribution curve is skewed to the right of the diagonal, the concentration index is negative. When the distribution curve of the health variable lies below the diagonal, it has a positive value. Further, it is vital to note that regarding the Gini coefficient, the concentration index will have the same absolute value as the Gini coefficient if the findings do not fluctuate owing to the sorting of socioeconomic and health factors. Consequently, without income-related inequality, the concentration index would equal 0. The concentration curve may be plotted, and the concentration index can be calculated with the help of a statistical program like STATA, or one can even use cumulative health measures and wealth as a variable in excel to depict the concentration curve and index.
Health Inequities: Cause, effect and ways to track #
One of the key causes of health inequalities is an unequal distribution of income, power, and money. People and communities may become poor and marginalized as a result. These underlying causes also impact how health-related environmental factors are distributed more broadly, such as the accessibility of services, suitable housing, economic opportunities, educational opportunities, and social and cultural opportunities in a community or society. It contributes to the previously described consequences, namely an unjust and unequal distribution of sickness, death, and health. It has consequences that extend beyond health inequities.
Societies with higher income, power, and wealth disparities among their citizens perform worse regarding various health and social consequences, including violence. Furthermore, there are regional differences in the degree of adult health disparities, and some nations provide better-targeted health subsidies for the underprivileged. The concentration index may quantify these and other differences between countries and effectively capture changes in health inequalities over time.
