Professor Mattes is also the director of the Democracy in Africa Research Unit in the Centre for Social Science Research, University of Cape Town. He is also Senior Adviser to, and co-founder of Afrobarometer, a ground-breaking regular survey of public opinion in 35 African countries.

He is also the co-author (with Michael Bratton and E. Gyimah-Boadi) of Public Opinion, Democracy and Markets In Africa (Cambridge University Press, 2005), and the co-editor (with David Denemark and Richard Niemi) of Growing Up Democratic: Does It Make A Difference? (Lynne Rienner Publishers, 2016).