Setting weights for aggregate indices: An application to the commitment to development index and human development index

Aggregate indices like UNDP's Human Development Index (HDI) or the Centre for Global Development and Foreign Policy's Commitment to Development Index (CDI) are subject to multiple criticisms. This paper addresses concerns linked to the equal weights used in the HDI and the CDI and evaluates alternative weighting schemes. It relies on an opinion survey conducted electronically among researchers from 60 countries to assess whether or not professional judgment affects the use of equal weights. Results of the opinion survey point to a surprising result for the HDI: despite widespread criticism of equal weights, a simple scheme based on equal weights is not only convenient but also consistent with the views of experts. For some components of the CDI, however, weights derived from the survey do differ from equal weights. Nevertheless, the weights emerging from the survey are not sufficiently different from equal weights to significantly alter country rankings.