The notion of “value creation” is central to strategy, but its exact meaning is often unclear. Confusion arises because value creation can be reasonably defined in two different ways: (1) as the total economic value created by a firm within a specific interval of time, and (2) as the change in this value over longer intervals. To formalize the latter notion of value creation, we introduce the concept of economic gain, defined as the increase in economic surplus generated by the firm between one time period and another. We discuss the advantages of this concept and show that economic gain can arise through innovation and improvement or through the growth and replication of a superior firm. We complement these discussions with a formal measurement framework that quantifies economic gain from innovation and its distribution among stakeholders, including the firm’s shareholders, managers, employees, suppliers, and customers. As an empirical illustration, we apply the framework to compare value creation and distribution by Southwest Airlines and American Airlines between 1980 and 2010.