The Sensitivity of the Human Development Index to Assumptions about Income

The Human Development Index (HDI) aims to present a more robust picture of a country’s development status than that suggested by national income per capita. The HDI aggregates dimension indices based on transformed measures for the core values of health, education, and income per capita. Assumptions are made regarding the upper and lower bounds used to re-scale each core value into its dimension index, as well as the functional form used to create the HDI. The treatment of income in the HDI’s construction suggests incompatibilities with its underlying capability theory, which stresses the importance of individuals’ abilities to make their own consumption and life choices. We examine the currently formulated HDI, as well as two influential proposed alternatives which generalize the aggregation functions of the pre-2010 HDI formulation and the current HDI, in light of recent empirical research into the relationship between well-being and income. We use underlying data for 2016, a representative year, to examine distributional changes as well as specific country rankings. We find that the income bounds used to calculate the income dimension index in the HDI should be changed. We also suggest that the three aggregation formulations, along with prominent descriptions of the assumptions and consequent implications of each approach, should be disseminated for policymakers and the public to consider.