He was the inaugural Edmond D. Villani Professor of Economics at Georgetown University,[2] and had previously been director of the research department at the World Bank.

[7] He advised numerous governments and international agencies, and wrote five books and 250 papers in scholarly journals, as well as editing several volumes.

His book The Economics of Poverty: History, Measurement, and Policy was published by Oxford University Press in January 2016.

In 2011 he received the John Kenneth Galbraith Award from the American Agricultural and Applied Economics Association.

He won the 2015 BBVA Foundation Frontiers of Knowledge Award in Development Cooperation for his groundbreaking work on defining the extreme poverty threshold with internationally applicable standards that facilitate the establishment of specific development cooperation goals.