Cooperation in the Classroom: Experimenting with Research Joint Ventures

This paper describes a classroom exercise that illustrates the investment incentives facing firms when technological spillovers are present. The game involves two stages in which student “sellers” first make investment decisions then production decisions. The classroom game can be used to motivate discussions of research joint ventures, the free-rider problem, collusion, and antitrust policy regarding research and development.

Caught in the Bulimic Trap? Persistence and State Dependence of Bulimia Among Young Women

Eating disorders are an important and growing health concern, and bulimia nervosa (BN) accounts for the largest fraction of eating disorders. Health consequences of BN are substantial and especially serious given the increasingly compulsive nature of the disorder. However, remarkably little is known about the mechanisms underlying the persistent nature of BN. Using a unique panel data set on young women and instrumental variable techniques, we document that unobserved heterogeneity plays a role in the persistence of BN, but strikingly up to two thirds is due to true state dependence. Our findings have important implications for public policy since they suggest that the timing of the policy is crucial: preventive educational programs should be coupled with more intense (rehabilitation) treatment at the early stages of bingeing and purging behaviors. Our results are robust to different model specifications and identifying assumptions.Bulimia Nervosa, Demographics, State Dependence, Instrumental Variables, Dynamic Panel Data Estimation, and Addiction

Will You Still Want Me Tomorrow? The Dynamics of Families' Long-Term Care Arrangements

We estimate dynamic models of elder-care arrangements using data from the Assets and Health Dynamics Among the Oldest Old Survey. We model the use of institutional care, formal home health care, care provided by a child, and care provided by a spouse in the selection of each care arrangement, the primary arrangement, and hours in each arrangement. Our results indicate that both observed heterogeneity and true state dependence play roles in the persistence of care arrangements. We find that positive state dependence (i.e., inertia) dominates caregiver burnout, and that formal care decisions depend on the cost and quality of care.Dynamic Models, Long-Term Care, Home Health Care, Informal Care

Advertising in the US Personal Computer Industry

Traditional models of consumer choice assume consumers are aware of all products for sale.This assumption is questionable, especially when applied to markets characterized by a high degree of change, such as the personal computer (PC) industry. I present an empirical discrete-choice model of limited information on the part of consumers, where advertising influences the set of products from which consumers choose to purchase. Multi-product firms choose prices and advertising in each medium to maximize their profits. I apply the model to the US PC market, in which advertising expenditures are over $2 billion annually. The estimation technique incorporates macro and micro data from three sources. Estimated median industry markups are 19% over production costs. The high industry markups are explained in part by the fact that consumers know only some of the products for sale.Indeed estimates from traditional consumer choice models predict median markups of one fourth this magnitude. I find that product-specific demand curves are biased towards being too elastic under traditional models of consumer choice. The estimates suggest that PC firms use advertising media to target high-income households, that there are returns to scope in group advertising, and that word-of-mouth or experience plays a role in informing consumers. The top firms engage in higher than average advertising and earn higher than average markups.

Caught in the Bulimic Trap? Persistence and State Dependence of Bulimia Among Young Women

Eating disorders are an important and growing health concern, and bulimia nervosa (BN) accounts for the largest fraction of eating disorders. Health consequences of BN are substantial and especially serious given the increasingly compulsive nature of the disorder. However, remarkably little is known about the mechanisms underlying the persistent nature of BN. Using a unique panel data set on young women and instrumental variable techniques, we document that unobserved heterogeneity plays a role in the persistence of BN, but strikingly up to two thirds is due to true state dependence. Our results, together with support from the medical literature, provide evidence that bulimia should be considered an addiction. Our findings have important implications for public policy since they suggest that the timing of the policy is crucial: preventive educational programs should be coupled with more intense (rehabilitation) treatment at the early stages of bingeing and purging behaviors. Our results are robust to different model specifications and identifying assumptions.bulimia nervosa, demographics, state dependence, instrumental variables, dynamic panel data estimation, addiction

Do research joint ventures serve a collusive function?

Every year thousands of firms are engaged in research joint ventures (RJV), where all knowledge gained through R&D is shared among members. Most of the empirical literature assumes members are non-cooperative in the product market. But many RJV members are rivals leaving open the possibility that firms may form RJVs to facilitate collusion. We examine this by exploiting variation in RJV formation generated by a policy change that affects the collusive benefits but not the research synergies associated with a RJV. We use data on RJVs formed between 1986 and 2001 together with firm-level information from Compustat to estimate a RJV participation equation. After correcting for the endogeneity of R&D and controlling for RJV characteristics and firm attributes, we find the decision to join is impacted by the policy change. We also find the magnitude is significant: the policy change resulted in an average drop in the probability of joining a RJV of 34% among telecommunications firms, 33% among computer and semiconductor manufacturers, and 27% among petroleum refining firms. Our results are consistent with research joint ventures serving a collusive function

Caught in the bulimic trap? Persistence and state dependence of bulimia among young women

Eating disorders are an important and growing health concern, and bulimia nervosa (BN) accounts for the largest fraction of eating disorders. Health consequences of BN are substantial and especially serious given the increasingly compulsive nature of the disorder. However, remarkably little is known about the mechanisms underlying the persistent nature of BN. Using a unique panel data set on young women and instrumental variable techniques, we document that unobserved heterogeneity plays a role in the persistence of BN, but strikingly up to two thirds is due to true state dependence. Our results, together with support from the medical literature, provide evidence that bulimia should be considered an addiction. Our findings have important implications for public policy since they suggest that the timing of the policy is crucial: preventive educational programs should be coupled with more intense (rehabilitation) treatment at the early stages of bingeing and purging behaviors. Our results are robust to different model specifications and identifying assumptions