Siebert also served as a member of both the Group of Economic Analysis (GEA) and the Group of Economic Policy Analysis (GEPA), a number of "European economists who advise the European Commission’s president.
From 2005 to 2007, as a member of GEPA, he advised EU President Jose Manuel Barroso[2] Siebert spent most of his academic career at the University of Kiel, where he held the chair for economic theory from 1989 to 2003.
Five years later, Siebert was appointed to the chair of economic theory at the University of Kiel.
Wie man Irrwege der Wirtschaftspolitik vermeidet,[5] he illustrated the causes of perverse incentives in economy and politics in referring to the so-called cobra effect.
He held the Heinz Nixdorf Chair in European Integration and Economic Policy at Johns Hopkins University's Paul H. Nitze School of Advanced International Studies, Bologna Center.