FERDI proposes an index of tax effort which takes into account the different dimensions of structural vulnerability for a large sample of developing countries over the last 3 decades.

FERDI uses 2 composite indicators - the Economic Vulnerability Index and the Human Assets Index - built and used by the United Nations to identify Least developed countries, for which historical time series are provided by the FERDI. The results support our view that these 2 dimensions should be taken into account in assessing tax effort for developing countries. FERDI  finds that economic vulnerability is harmful to tax revenue while human assets enhance tax revenues.

This estimation of a new tax effort index has been calculated for 120 developing countries over the period 1990-2012.