 His comparative historical research has challenged left and right both, from Stephen Pimpare to the Cato Institute, and has featured in encyclopedias on social work.Ziliak's historical research on previous attempts to privatize welfare for the poor has questioned the virtue-ethical philosophies of Victorians, Old and New, from Herbert Spencer to Gertrude Himmelfarb.In "The Bourgeois Virtues" (2006, xviii) his former dissertation adviser and long-time coauthor Deirdre N. McCloskey thanks Ziliak (together with Arjo Klamer and Helen McCloskey, Deirdre's mother) for "disagreeing with me about the bourgeois virtues".