We study how firms differ from their competitors using new dynamic measures of product differentiation based on novel text based analysis of 50,673 product descriptions from firm 10-K statements filed yearly with the Securities Exchange Commission. This year-by-year set of firm product differentiation measures allows us to generate a set of dynamic industry classifications and new measures of industry structure and competition. Competitiveness and market structure measures based on these new classifications better correlate with firm profitability than do classifications based on SIC or NAICs. Using these new dynamic industry classifications, we examine endogenous product differentiation. We show that firms use R & D and advertising to differentiate themselves from competitors and increase their profitability.

We study how firms differ from their competitors using new time-varying measures of product differentiation based on text-based analysis of product descriptions from 50,673 firm 10-K statements filed yearly with the Securities and Exchange Commission. This year-by-year set of product differentiation measures allows us to generate a new set of industries and corresponding new measures of industry competition where firms can have their own distinct set of competitors. Our new sets of industry competitors better explain specific discussion of high competition by management, rivals identified by managers as peer firms and firm characteristics such as profitability and leverage than do existing classifications. We also find evidence that firm R&D and advertising are associated with subsequent differentiation from competitors, consistent with theories of endogenous product differentiation.

There are few industries in modern market economies that do not manufacture differentiated products. This book provides a systematic explanation and analysis of the widespread prevalence of this important category of products. The authors concentrate on models in which product selection is endogenous. In the first four chapters they consider models that try to predict the level of product differentiation that would emerge in situations of market equilibrium. These market equilibria with differentiated products are characterised and then compared with social welfare optima. Particular attention is paid to the distinction between horizontal and vertical differentiation as well as to the related issues of product quality and durability. This book brings together the most important theoretical contributions to these topics in a succinct and coherent manner. One of its major strengths is the way in which it carefully sets out the basic intuition behind the formal results. It will be useful to advanced undergraduate and graduate students taking courses in industrial economics and microeconomic theory.

Sunk Costs and Market Structure bridges the gap between the new generation of game theoretic models that has dominated the industrial organization literature over the past ten years and the traditional empirical agenda of the subject as embodied in the structure-conduct-performance paradigm developed by Joe S. Bain and his successors.