When more does not necessarily mean better: Health-related illfare comparisons with non-monotone welfare relationships

Most welfare studies are based on the assumption that wellbeing is monotonically related to the variables used for the analysis. While this assumption can be regarded as reasonable for many dimensions of wellbeing like income, education, or empowerment, there are some cases where it is definitively not relevant, in particular with respect to health. For instance, health status is often proxied using the Body Mass Index (BMI). Low BMI values can capture undernutrition or the incidence of severe illness, yet a high BMI is neither desirable as it indicates obesity. Illfare estimattions derived from usual poverty measures are then not appropriate. This paper proposes poverty indices that are consistent with some situations of non-monotonic wellbeing relationships and examines the partial orderings of different distributions derived from various classes of poverty indices. An illustration is provided for health-related illfare as proxied by the BMI using DHS data for Bangladesh during the period 1997–2007. It is shown that the gains of the decline of undernutrition are undermined by the rapid increase of obesity.