Changes in Product Attributes and Costs as Drivers of New Product Diffusion and Substitution

Diffusion theory has typically focused on how communication, internal or external to a social system, leads to adoptions and diffusion of an innovation. We develop a diffusion and substitution model based on a somewhat different perspective. In some cases, progressive improvements in product attributes and/or continual cost reduction seem to be a key driver of the diffusion process. For example, after introduction of the 5.25‐inch disk drive, its capacity continually increased, and accordingly, so did customer willingness‐to‐pay. Our model is based on a linear reservation price framework, in which a product is described by its depth (defined as the difference between a product̂s maximum reservation price and its production cost), and its breadth (related to the slope of its reservation price curve), indicating how broadly it appeals across various customer segments. Because of changes in product depths and breadths over time, customers who previously preferred the old product may later prefer the new product, thus creating the diffusion process. While the Bass model describes diffusion as a function of the coefficients of innovation and imitation, in our model, it is described by the coefficients of depth and breadth (the rates of change in relative depth and breadth), along with an S‐coefficient that we associate with the technology S‐curve. We fit our model to data from the disk‐drive and the microprocessor industries.     

Discrete–Time Approximations of the Holmström–Milgrom Brownian–Motion Model of Intertemporal Incentive Provision

This paper studies the relation between discrete–time and continuous–time principal–agent models. We derive the continuous–time model as a limit of discrete–time models with ever shorter periods and show that optimal incentive schemes in the discrete–time models approximate the optimal incentive scheme in the continuous model, which is linear in accounts. Under the additional assumption that the principal observes only cumulative total profits at the end and the agent can destroy profits unnoticed, an incentive scheme that is linear in total profits is shown to be approximately optimal in the discrete–time model when the length of the period is small.     

Do Political Institutions Shape Economic Policy?

Do political institutions shape economic policy? I argue that this question should naturally appeal to economists. Moreover, the answer is in the affirmative, both in theory and in practice. In particular, recent theoretical work predicts systematic effects of electoral rules and political regimes on the size and composition of government spending. Results from ongoing empirical work indicate that such effects are indeed present in the data. Some empirical results are consistent with theoretical predictions: presidential regimes have smaller governments and countries with majoritarian elections have smaller welfare‐state programs and less corruption. Other results present puzzles for future research: the adjustment to economic events appears highly institution‐dependent, as does the timing and nature of the electoral cycle.     

Insurance demand and social comparison: An experimental analysis

This paper analyzes whether social comparison can explain the low take-up of disaster insurance usually reported in field studies. We argue that risks in the case of disasters are highly correlated between subjects whereas risks for which high insurance take-up can be observed (e.g. extended warranties or cell phone insurance) are typically idiosyncratic. We set up a simple model with social reference points and show that in the presence of inequality aversion social comparison makes insurance indeed less attractive if risks are correlated. In addition we conducted a simple experiment which confirms these theoretical results. The average willingness to pay for insurance is significantly higher for idiosyncratic than for correlated risks.     

Matching Product Architecture and Supply Chain Configuration

In this paper, we examine the suggested link between product architecture (i.e., the extent to which a product is modular vs. integral) and supply chain configuration (i.e., whether the product development is done internally by the manufacturer in an integrated supply chain or in collaboration with a supplier in a decentralized supply chain). Our model suggests that the choice of product architecture depends on firm, market, and product characteristics in addition to supply chain structure. In contrast to other studies, we find that the optimal mapping from architecture to supply chain structure is not always one‐to‐one. A decentralized supply chain may be associated with a more integral product when the technical collaboration penalty is not excessive and suppliers have significantly superior product development capabilities. Furthermore, in a decentralized supply chain, the nature of the relationship between the original equipment manufacturer and its supplier (adversarial or collaborative) plays a role in the choice of product architecture: modular architectures are more likely when the parties have adversarial relationships, while long‐term trust‐based relationships facilitate more integral product architectures.     

Testing transitivity in choice under risk

Recently proposed models of risky choice imply systematic violations of transitivity of preference. This study explored whether people show the predicted intransitivity of the two models proposed to account for the certainty effect in Allais paradoxes. In order to distinguish “true” violations from those produced by “error,” a model was fit in which each choice can have a different error rate and each person can have a different pattern of preferences that need not be transitive. Error rate for a choice is estimated from preference reversals between repeated presentations of the same choice. Results showed that few people repeated intransitive patterns. We can retain the hypothesis that all participants were transitive.     

Autorität? Führung? Macht?

The topic of education and learning currently being debated with much fervor in the public arena reflects the process of change within postmodern society and its impact on the development of children and adolescents. This discussion grapples with the issue of the authority of parents and teachers as well as their role in the context of family and school. The task of trying out new roles and agreeing on them is of pre-eminent importance, since traditional role models are no longer tenable. In doing so, the relation between hierarchy and discourse is being established anew.     

Childhood Sexual Experiences and Adult Health Sequelae Among Gay and Bisexual Men: Defining Childhood Sexual Abuse

Gay and bisexual men carry the burden of HIV infections in the United States and have high rates of childhood sexual abuse that predict HIV and other health outcomes. This study examined differential effects of forced, consensual, and no childhood sexual experiences (CSE) on health outcomes among a probability sample of adult men who have sex with men (MSM). The forced sex group had the highest levels of psychological distress, substance use, and HIV risk. There were no differences in rates of depression and suicidal ideation between the consensual- and no-sex groups. The consensual- and forced-sex groups had higher rates of substance use and transmission risk than the no-sex group. The forced-sex group, however, had significantly higher rates of frequent drug use and high-risk sex than the consensual group. Findings suggest that forced CSEs result in a higher-risk profile than consensual or no childhood sexual experiences, the kind of risk pattern differs between forced and consensual childhood sexual experiences, and the underlying mechanisms that maintain risk patterns may vary. It is important to clarify risk patterns and mechanisms that maintain them differentially for forced and consensual sex groups so that interventions may be tailored to the specific trajectories related to each experience.     

Childhood sexual experiences and adult health sequelae among gay and bisexual men: defining childhood sexual abuse

Gay and bisexual men carry the burden of HIV infections in the United States and have high rates of childhood sexual abuse that predict HIV and other health outcomes. This study examined differential effects of forced, consensual, and no childhood sexual experiences (CSE) on health outcomes among a probability sample of adult men who have sex with men (MSM). The forced sex group had the highest levels of psychological distress, substance use, and HIV risk. There were no differences in rates of depression and suicidal ideation between the consensual- and no-sex groups. The consensual- and forced-sex groups had higher rates of substance use and transmission risk than the no-sex group. The forced-sex group, however, had significantly higher rates of frequent drug use and high-risk sex than the consensual group. Findings suggest that forced CSEs result in a higher-risk profile than consensual or no childhood sexual experiences, the kind of risk pattern differs between forced and consensual childhood sexual experiences, and the underlying mechanisms that maintain risk patterns may vary. It is important to clarify risk patterns and mechanisms that maintain them differentially for forced and consensual sex groups so that interventions may be tailored to the specific trajectories related to each experience.     

Gender Minority Stress: A Critical Review

ABSTRACT

Past studies that compare cisgender to transgender (or trans) and gender diverse people have found a higher prevalence of mental health problems among the latter groups. This article uses Testa’s gender minority stress framework, which is an expansion of minority stress theory, to assess minority stressors that are specific to the experiences of trans and gender diverse people. The concept of cisnormativity, an ideology that positions cisgender identities as a norm, is used in relation to the gender minority stress framework to describe the marginalizing nature of social environments for trans and gender diverse people. This article provides a critical review that integrates and expands on past theoretical perspectives on gender minority stressors and protective factors. Specifically, this article demonstrates the relevance of cultural and ethnic backgrounds to complement the application of intersectionality in research on health disparities experienced by trans and gender diverse people.