 He subsequently got his doctorate in 1978 at the University of Aix-Marseille in France.In 1953, Maddison joined the Organisation for European Economic Cooperation (OEEC), and afterwards became Head of the OEEC Economics Division.In 1963, when the OEEC became the Organisation for Economic Co-operation and Development (OECD), Maddison became Assistant Director of the Economic Development Department.