[2] Withers' research interests span the fields of economy, society, and culture, with a particular focus on public policy regarding human capabilities and knowledge including labour, immigration, and education.
Subsequently, he served as a Research Fellow in Economics at the Institute of Advanced Studies at the Australian National University (ANU) until 1978.
[8] Withers held the position of Chair of the Task Force on Population Issues for Prime Minister Bob Hawke[9] and Chair of the Task Force on Private Infrastructure Provision for Prime Minister Paul Keating.
[10] He was co-chair of the National Population Council, convening its Immigration Selection Systems Review.
[11] He was appointed by the Abbott Government to provide a Strategic Review of Employment Participation Programs for Cabinet.
[12] Withers has authored more than 200 peer-reviewed articles[13] Key research topics have included: gains from volunteer military recruitment,[14] efficiency benefits from banking deregulation,[15] relationship of immigration to aggregate unemployment, provision of incentives for regional and international student migrations,[16] efficiency of public broadcasting,[17] implications of federal governance, public value of cultural support including for arts and journalism,[18] comparative standing of alternative wage-fixing systems,[19] labor market forecasting,[20] costs for higher education provision,[21] and social dimensions of cybersecurity.