Title: Business model evaluation
Description: In recent years, the concept of the business model has received substantial attention in the strategy literature, where a number of qualitative approaches to describe, represent, and evaluate business models have been proposed. We contend that while helpful to understand a firm's overall logic of value creation and capture, qualitative methods must be complemented with quantitative analyses. The development of quantitative methods for the study of business models, however, has trailed that of their qualitative peers. In this paper, we develop an analytical framework based on the theory of index numbers and production theory to provide quantitative insight on the link between a firm's business model choices and their ultimate profit consequences. We apply the method to Walmart. Using evidence from annual reports, research papers, case studies, and books for the period of 1972-2008, we build a qualitative representation of Walmart's business model.

We then map that representation to an analytical model that quantifies Walmart's sources of competitive advantage over a 36-year period. Although Walmart's business model remained the same during the years of our study, we find that the different CEOs pulled a number of business model levers differently, which partly explains the variation in Walmart's performance throughout the years. Under Sam Walton, the company's performance improved due mainly to the adoption of new technologies as well as low prices obtained from vendors. David Glass's tenure was characterized by business model choices aimed at increasing volume such as building new stores, increasing product variety, everyday low prices (EDLP), and high-powered incentives for store managers. Input and output prices played a smaller role under David Glass than under Sam Walton.

Finally, Lee Scott loosened EDLP and modified Walmart's human resource practices by offering better benefits and wages to associates in response to growing social pressure. Overall, our analysis suggests that the effectiveness of a particular business model depends not only on its design (its levers and how they relate to one another) but, most importantly, on its implementation (how the business model levers are pulled).