As a conscientious objector, Vidar Halvorsen (born 1953) served his alternative national service at PRIO in 1981–82, Following final exams in political science at the University of Oslo, he served several years in the public sector before joining the Department of Criminology and Sociology of Law at the University of Oslo, from 2013 as Professor of Sociology of Law. He became Professor emeritus in 2023.