Knowledge, an essential production factor in the post-industrial society, is not as rigorously measured as organizational tangibles. Several authors in the tradition of intellectual capital measurement and human resource accounting have tried to solve this by the development of one or more metrics. This chapter assumes that valuation is intrinsically subjective and that knowledge to a large extent is subjective. Consequently, it should be approached by subjective valuation methods. The chapter reviews existing knowledge valuation methods for their validity for a specific stakeholder group, and considers Nominal Group Techniques as a way to converge the resulting opinions. This convergence is important for shared decision-making. Following this approach, knowledge valuation is not accounting but much more the creation and facilitation of productive cooperative systems in the economy.