Magnus has worked as a consultant or sub-contractor for private international organizations like DAI Brussels, KPMG Ghana, Ernst & Young Ghana, and Japanese Organization for International Cooperation in Family Planning (JOICFP), and multilaterals like the World Bank and UN Economic Commission for Africa (UNECA). Countries that he has undertaken consultancy works include Ghana, the Gambia, Liberia, and Nigeria.

He also worked at the Swiss State Secretariat for Economic Affairs (SECO) as the Macroeconomist and Financial Sector Specialist; as Senior Research Fellow at the Institute for Fiscal Studies (IFS); and Economist Adviser for the Field Support Services Program (FSSP) of Global Affairs Canada’s (GAC) programs in Ghana.

He is a member of the International Association of Researchers in Income and Wealth (IARIW) and Institute of Chartered Economist of Ghana (ICEG). He previously served on the UNSD Advisory Expert Group on National Accounts Statistics, IMF Expert Portal on National Accounts and Price Statistics, and ECOWAS Expert Group Meeting on National Accounts and Price Statistics.

Among his achievements are: The first Ghanaian to rebase Ghana’s GDP to 2006 base year (previous rebasing exercises were done by IMF consultants); Led a team to develop Data Quality Assessment Framework (DQAF) for the Gambia; and the first person to estimate subnational GDP (the GDP for the city of Accra) in Ghana using the best international standard approach. He also has eight (8) publications (both published and unpublished) to his credit.