Although strategic management research is well aware of the importance of construct measurement, surprisingly little rigor is applied regarding its core concept, firm performance. Using the example of the resource-based view (RBV), this paper demonstrates how divergence between theory-building and construct measurement regarding firm performance can produce misleading conclusions. The RBV seeks to explain value creation in the marketplace, yet empirical studies often measure various aspects of firm financial performance. Building on appropriation theory, I show that it is not possible to infer to changes in firm value creation from observed changes in firm financial performance measures and vice versa due to an omitted variable bias: the neglect of the relative bargaining power of stakeholders. This paper derives conclusions for research practice and suggests theoretically meaningful ways of bridging the gap between value creation and firm financial performance in the RBV framework.