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useful conversations. We thank the Searle Foundation and the Kaufman Foundation for funding. All errors are our responsibility. Abstract How much economic value did the diffusion of broadband create? We provide benchmark estimates for 1999 to 2006. We observe $39 billion of total revenue in Internet access in 2006, with broadband accounting for $28 billion(More)
Pakes for valuable advice and assistance. I am especially grateful to Benjamin Mordecai for sharing with me his insights into theatre ticket pricing and for his interest in the study from the very beginning, and to Christina Mills for assisting me to obtain the data. Finally, I thank the Cowles Foundation for financial support in the form of a Carl Arvid(More)
We provide a new and more complete analysis of the origins of the Dust Bowl of the 1930s, one of the most severe environmental crises in North America in the twentieth century. Severe drought and wind erosion hit the Great Plains in 1930 and lasted through 1940. There were similar droughts in the 1950s and 1970s, but no comparable level of wind erosion. We(More)
I address a recent critique by Corts [1999] who finds that traditional approaches in New Empirical Industrial Organization to estimate the competitive conduct in an oligopoly market can yield inconsistent estimates of the conduct parameter if firms are engaged in efficient collusion. This paper derives a general empirical model that allows consistent(More)
for useful conversations and to many seminar participants. Abstract This papers provides a framework for organizing empirical research on structural change in electronic commerce at the nexus between infrastructure and virtual activity. The framework identifies several key questions for understanding the evolution of the value chain underlying electronic(More)
DOCK8 mutations result in an inherited combined immunodeficiency characterized by increased susceptibility to skin and other infections. We show that when DOCK8-deficient T and NK cells migrate through confined spaces, they develop cell shape and nuclear deformation abnormalities that do not impair chemotaxis but contribute to a distinct form of(More)
Consumer privacy and the market for customer information in electronic retailing are investigated. The value of customer information derives from the ability of firms to identify individual consumers and charge them personalized prices. Two settings are studied, an anonymity regime in which sale of customer information is not possible, and a recognition(More)
Traditional models of consumer choice assume consumers are aware of all products for sale. But in markets characterized by a high degree of change, such as the personal computer (PC) industry, this full information assumption is untenable. I present a discrete-choice model of limited consumer information, where advertising influences the set of products(More)
Why do businesses such as fast-food restaurants, coffee shops, and hotels cluster? In the classic analysis of Hotelling, firms cluster to attract consumers who have travel costs. We present an alternative model where firms cluster because one firm is free riding on another's information about market demand. One consequence of this free riding is that an(More)
Patients with the dedicator of cytokinesis 8 (DOCK8) immunodeficiency syndrome suffer from recurrent viral and bacterial infections, hyper-immunoglobulin E levels, eczema, and greater susceptibility to cancer. Because natural killer T (NKT) cells have been implicated in these diseases, we asked if these cells were affected by DOCK8 deficiency. Using a mouse(More)