The literature on the accounting profession has undergone something of a resurgence in recent years, stimulated not just by recent concerns about independence, but also by detailed historical and ethnographic examinations of practice, and theories of inter-professional competition (Cooper & Robson, forthcoming). The present paper contributes to this literature through the development of a better understanding of the processes by which accountants and auditors come to be recognized as possessing relevant expertise in new domains. In so doing, we contribute to debates about professions and the production of professional expertise. Specifically, we have explored the claim making and networking involved in conducting new forms of work. Below we review and extend our observations about the construction of expertise in auditing performance measures (both financial and non-financial), and the more general view that government auditors are experts in crucial components of NPM.