A Convolution Estimator for the Density of Nonlinear Regression Observations

Abstract. The problem of estimating an unknown density function has been widely studied. In this article, we present a convolution estimator for the density of the responses in a nonlinear heterogenous regression model. The rate of convergence for the mean square error of the convolution estimator is of order n ^?1 under certain regularity conditions. This is faster than the rate for the kernel density method. We derive explicit expressions for the asymptotic variance and the bias of the new estimator, and further a data‐driven bandwidth selector is proposed. We conduct simulation experiments to check the finite sample properties, and the convolution estimator performs substantially better than the kernel density estimator for well‐behaved noise densities.     

The MySocialworker app system – a pilot interview study

An app system was developed in Denmark by caseworkers and clients from three municipalities, a software company, and a University College. The app system enabled young clients to track their wellbeing, positive behaviours, disturbances in their lives, and their experiences of interventions on smartphones. Statutory caseworkers could follow the change in their client’s situation and have an overview of all their clients on a web interface. This article describes the system and the results of a pilot qualitative interview study with six young clients. Clients used the app to reflect on their lives, to set specific personal goals and to remember their goals. The young clients also used the app to monitor changes in how they had been doing overall and as a reminder to keep up specific behaviours that were counterintuitive. The app became an integral part of the young clients’ relationship with their caseworker. The app was a lens that the client and the caseworker used to explore specific aspects of the client’s life. The app itself also became a joint venture, a shared point of interest. The app strengthened the young persons’ relationship with their caseworker, but there was also concern about whether they might become too close.     

DO EMPLOYERS PAY FOR CONSISTENT PERFORMANCE?: EVIDENCE FROM THE NBA

In a world of uncertainty in which a worker's performance is variable over time and average performance is unknown when hiring, how will employers determine compensation? We develop a monitoring and signaling model where information is symmetric and parties are risk neutral. Monitoring costs increase with inconsistency, lowering pay for inconsistent workers. If discrimination exists, minority workers will be rewarded less than majority workers for improving consistency. Testing these and other predictions using National Basketball Association data, we find that consistent professional basketball players are paid more, but, in contrast to previous studies, there is no evidence of discrimination. (JEL J3, J7)     

State Formation and the Politics of Regime Survival: Zimbabwe in Theoretical Perspective

This article analyses state formation in Rhodesia/Zimbabwe. The main question posed is this: Why has state power eroded so dramatically? To answer this question, the development of the state is analysed in the light of general theories of state formation. In spite of a situation which according to prevailing theories was conducive for the formation of a strong state, Zimbabwe entered a downward spiral, where state power gradually eroded. To explain this, it is necessary to move beyond these theories, and analyse the changing nature of the ruling regime's constituencies. While security threats and sources of revenue are important, their impact on processes of state formation is mediated by the inter‐relationship between ruling regimes and their constituencies, which is shaped by society's class structure.     

A fixed-effects multilevel analysis of how community family structure affects individual mortality in Norway

By using register data for the entire Norwegian population aged 50-89 in the period 1980-1999, during which there were about 720,000 deaths, I estimate how the proportions of persons who were divorced or never married in the municipality affected all-cause mortality, net of individual marital status. The data include individual histories of changes in marital status and places of residence, providing a rare opportunity to enter municipality fixed effects into the model, thereby capturing the time-invariant unobserved factors at that level. The positive health externality of marriage that is suggested in the literature is supported by some of the estimates for women. Other estimates--especially those for men--point in the opposite direction. One possible interpretation of these findings is that social cohesion is perhaps not as beneficial for people's health as often claimed, at least not for both sexes. Alternatively, the results may reflect that marriage perhaps undermines rather than strengthens social cohesion, or that other mechanisms are involved-for example, those that are related to people 's perceptions of their health relative to the health of others. Estimates from models without such municipality fixed effects are markedly different, but these also shed doubt on the notion that a high proportion of unmarried persons generally increases individual mortality.