Large Market Asymptotics for Differentiated Product Demand Estimators With Economic Models of Supply

IO economists often estimate demand for differentiated products using data sets with a small number of large markets. This paper addresses the question of consistency and asymptotic distributions of instrumental variables estimates as the number of products increases in some commonly used models of demand under conditions on economic primitives. I show that, in a Bertrand–Nash equilibrium, product characteristics lose their identifying power as price instruments in the limit in certain cases, leading to inconsistent estimates. The reason is that product characteristic instruments achieve identification through correlation with markups, and, depending on the model of demand, the supply side can constrain markups to converge to a constant quickly relative to sampling error. I find that product characteristic instruments can yield consistent estimates in many of the cases I consider, but care must be taken in modeling demand and choosing instruments. A Monte Carlo study confirms that the asymptotic results are relevant in market sizes of practical importance.     

A New Game In Town: Competitive higher education

Research universities in the USA are complex, expensive organizations that perform multiple interrelated tasks and serve numerous constituencies. The value structure that has evolved for these universities is one that creates very high barriers to entry for new players and numerous impediments to rapid change. Consequently, real competitive pressures on universities have been minimal. However, new types of for-profit and non-profit organizations are beginning to provide competition in targeted segments of higher education. The arrival of Internet-mediated distance learning will greatly increase both market penetration by these new organizations and competition between traditional institutions of higher learning. Because this new competition targets only selected activities of the research university, it risks to destabilize their organization and structure. Ways in which this destabilization might occur are analysed and possible responses are discussed.     

Relations between Temperament and Anger Regulation over Early Childhood

Theory suggests temperamental reactivity [negative affectivity (NA)] and regulation [effortful control (EC)] predict variation in the development of emotion regulation (ER). However, few studies report such relations, particularly studies utilizing observational measures of children's ER behaviors in longitudinal designs. Using multilevel modeling, the present study tested whether (1) between‐person differences in mean levels of mother‐reported child NA and EC (aggregated across age) and (2) within‐person changes in NA and EC from the ages of 18 to 42 months predicted subsequent improvements in laboratory‐based observations of children's anger regulation from the ages of 24 to 48 months. As expected, mean level of EC (aggregated across age) predicted longer latency to anger; however, no other temperament variables predicted anger expression. Mean level of EC also predicted the latency to a child's use of one regulatory strategy, distraction. Finally, decreases in NA were associated with age‐related changes in how long children used distractions and how quickly they bid calmly to their mother. Implications for relations between temperament and anger regulation are discussed in terms of both conceptual and methodological issues.     

Styles of illusion

This paper argues that one of the most prevalent styles in contemporary sociology‐style referring to a complex of theory, method and treatment of the literature‐systematically allows space for the misrepresentation of reality. The theoretical core of the style in question is a view of identity as formed through the active consumption of discourse, its preferred methodology is that of qualitative fieldwork whilst a largely impressionistic literature is treated as a source of authoritative commentary on the influence of specific discourses. The theoretical and methodological elements of this style interact so that its treatment of ethnographic data functions as a self‐fulfilling prophecy for whatever presuppositions can be constructed from its treatment of the literature. This thesis is illustrated through an analysis of the claims made by Paul du Gay (1996), and Musson and Cohen (1997) that enterprise discourse had achieved hegemonic status in the UK during the last decade of the Twentieth Century.     

Communicating About Xenotransplantation: Models and Scenarios

Xenotransplantation entails using organs from genetically modified animals as a way to solve the shortage of human organs for transplantation. As with other novel technologies, if xenotransplantation is to be judged fairly, proponents must explain its complex, uncertain, and unfamiliar risks and benefits. Xenotransplantation's risks include the possibility of a recombinant virus infecting human transplant recipients, potentially causing an epidemic of an unfamiliar disease. Using materials vetted by scientific experts, we communicated the variables and relationships determining this risk in three formally equivalent formats: (a) a graphic model, (b) scenarios structured by the graphic model, and (c) both the model and the scenarios. Participants were randomly assigned to receiving one set of materials. They rated them as equally clear and studied them equally long, suggesting similar ease of cognitive processing. Compared to participants receiving the scenarios, those who received the graphic model better identified causes and effects of the risk, and saw less risk of xenotransplantation. Participants who received both the model and the scenarios generally showed intermediate responses. The study demonstrates a general procedure for developing and evaluating formally equivalent graphic and scenario communications regarding highly uncertain risks. In this application to xenotransplantation, presenting a graphic representation improved people's understanding of the risk.     

Knowledge,attitudes, and behavior related to condom use and STDs in a high risk population

Since the mid‐1980s, the incidence of sexually transmitted diseases (STDs) among Blacks has increased dramatically nationwide, particularly in Philadelphia and other major urban areas. One approach to this public health problem is to prevent the further transmission of disease through the use of condoms during sexual activity. To provide a basis for condom‐promotion programs within a high risk Black urban community, we explored condom use behavior and the relationship between condom use and variables related to demographic characteristics, knowledge, attitudes, perceived risk and concern about STDs, and STD history. A household survey was conducted of a stratified, quota sample of 925 male and female adolescent and adult residents in North and West Philadelphia. These areas have the highest rate of STDs in the city and among the highest rates in the country. The survey revealed a trichotomy among respondents with respect to condom use: approximately one‐third of the sample used condoms consistently; one‐third used them intermittently, and one‐third never used condoms. Consistent condom users tended to use condoms with both steady and casual partners; less frequent condom users tended to use condoms with partners who could be considered higher risk: new partners and casual partners. Although condom use rates did not vary as a function of age among males, women under age 20 were far more likely to use condoms than were other female age groups. Knowledge about STDs and prevention was not found to predict condom use. Negative attitudes toward condoms were related to non‐use, with the exception of women who used condoms in perceived high risk situations despite negative attitudes.     

A Structured Literature Review for Risk Assessment: EMF and Human Health Risk

The volume of publications on any given topic makes it difficult to select an appropriate subset of publications for review by an expert panel. This paper proposes a method for selecting a subset using a protocol that attempts to order publications based upon good research methods. The protocol was followed by graduate students with no expert knowledge of the area they were reviewing. They reduced 11730 articles on the topic of EMF and Health risk to 68 articles that were reviewed by an expert panel. The interrater reliability was 96% and 94% of the relevant articles were captured by this process.