Application of Gini, Theil and concentration indices for assessing water use inequality

Purpose The purpose of this paper is to propose the application of Gini, Theil and concentration indices for measuring inequality in water usage. Design/methodology/approach Gini coefficients and Theil indices have been used to estimate the overall inequality in domestic water use in a sample of 30 countries around the world. Along with Theil’s L (unweighted) index, liters per capita per day and gross national income weighted Theil index have also been estimated. Theil indices have been further disintegrated into within- and between-group inequalities. Concentration curve is also constructed to study the inequality in water use in accordance to the countries’ economic standing. Findings Domestic water use is high among the well-off countries considered in the study. Also, the Theil indices indicate that between group inequality contributes more to the overall inequality. It is observed that Theil indices, which consider only per capita water usage and can be decomposed, give a better insight into the existing inequality. Practical implications Different approaches were used to quantify inequality. The choice of index depends on the context of the study. The proposed approaches can contribute to planning of sustainable water management and development policies. Originality/value There is a dearth of metrics for quantifying inequality in water access or use. The study presents the application of indices, widely used in quantifying inequality in access to other resources such as income and energy, in assessing water inequality.