As the Introduction to this book has argued, governmental use of consultancy services has long been a concern for scholars of public administration, management and political science (Howlett and Migone 2013a, 2013b; Kipping and Engwall 2003; Graeme and Bowman 2006; Guttman and Willner 1976; Rosenblum and McGillis 197).Although the impact of policy consulting is generally expected to be fairly broad, most of these studies have focused on a narrow set of questions related to the effect of contracting out on levels of public service employment and budgets (Dilulio 2016; Guttman and Willner 1976; GAO 2011) rather than on policy outcomes. Much existing research has focused either on placing this expansion in a historical perspective (McKenna 1995, 1996, 2006), or assessing its underlying causes and consequences (David 2012; Berit and Kieser 2002; McGann 2007).