Professionals and students of strategy are hungry for reliable, fact-based approaches to analyzing business performance and developing strategy. They especially need to understand what drives performance through time, not only to communicate and persuade others of desirable initiatives, but also to provide a sound basis for investors to value firms and their plans. Common approaches to strategy are often derived from statistical methods, and are inadequate for responding to this need for time-based understanding. In contrast, the notion that business resources accumulate and deplete as time passes is readily understood by management, and is also amenable to rigorous analysis.