His research area is Industrial Organization, with particular emphasis on network economics. He is Associate Editor of Information Economics & Policy and Review of Economics. He has been a consultant for ICP-ANACOM and various international companies and institutions on issues in network competition. He was a jury member for the rural next-generation broadband competition in Portugal. Steffen obtained a Degree in Management at the U. Bielefeld (Germany); a Master in Applied Mathematical Sciences at U. Georgia, (Athens, USA); and a PhD in Economics at EUI (Florence, Italy).