Age-test Markov chains for drug testing and detection

Random urinalysis strategies stratified by time since the last test are characterized with a set of Markov chain models. The probability of a person being tested depends on the amount of time since the person's last test. The Nuclear Regulatory Commission (NRC) has proposed a two strata drug testing strategy based on time since last test. The proposal included a high testing rate for people not yet tested in a given time period and a low testing rate for people testing negative in a given time period. Southern California Edison has implemented a variation of the NRC proposal. These strategies can be modeled within a Markov chain framework. Time to detection is calculated as a function of testing probabilities and drug usage levels. Drug user gaming strategies are discussed with illustrations. These models are implemented as part of a U.S. Navy drug policy analysis system.     

The Effect of Respondent Experience/Knowledge in the Elicitation of Contingent Values: An Investigation of Convergent Validity,Procedural Invariance and Reliability

Tests of convergent validity and procedural invariance were used to investigate whether individuals lacking direct experience with a commodity can provide valid responses to contingent-valuation questions eliciting ex post use values. Convergent validity between samples with and without experience was shown to hold for dichotomous-choice responses, but not for open-ended responses.     

Short Positions in the First Principal Component Portfolio

Insurance companies and pension plans typically hold well-diversified equity portfolios. These institutions are also often restricted from taking short positions. The diversification requirement operates on the portfolio level, while the short sale constraint is at the individual security level. We examine an investment strategy that exposes a tension between these two requirements. This strategy uses the first principal component to construct the portfolio and by design meets the first requirement. Empirical portfolios based on the first principal component do an excellent job of capturing market exposure and minimizing diversifiable risk. However, in practice such portfolios sometimes contain a few short positions. So this strategy does not always meet the second requirement. We examine which features of stock returns give rise to short positions when a portfolio is based on the first principal component, and we are able to identify the characteristics of the stocks that are responsible for the short positions. These stocks tend to have negative correlations with the majority of other stocks. In contrast such stocks would typically be held long in a Markowitz portfolio. We discuss and explain this puzzle.     

Rules,standards, and ethics: Relativism predicts cross-national differences in the codification of moral standards

This research examines the relationship between the code of ethics adopted by businesses in a country and the ethics positions of the inhabitants of that country. Ethics Position Theory (EPT) maintains that individuals’ personal moral philosophies influence their ethical judgments, actions, and emotions. The theory, when describing individual differences in moral philosophies, stresses two dimensions: relativism (skepticism with regards to inviolate moral principles) and idealism (concern for positive outcomes). Extending previous research that identified differences in relativism and idealism between residents of different countries and world regions, we examined the relationship between relativism, idealism, and the regulatory standards governing commercial activities of firms headquartered in Australia, Austria, Belgium, Canada, Hong Kong, Ireland, Japan, New Zealand, Spain, the UK, and the US. The results indicated that the level of relativism of a nation's populace predicted degree of ethical codification of commerce in that nation. These findings suggest that the ethical conduct of business will be more closely regulated in countries where relativism is low (e.g., Australia, Canada) but less closely regulated in countries where the residents are more ethically relativistic (e.g., Hong Kong, Spain).     

Nursing unit characteristics and patient outcomes

In this exploratory cross-sectional study, nursing unit organizational characteristics and how they influenced patient outcomes in the form of nurse-sensitive adverse events and failure to rescue were examined. Results showed significant associations between characteristics and adverse events at the unit level. Autonomy/collaboration was associated with pressure ulcer and failure to rescue, practice control with urinary tract infection, and continuity/specialization with death. Unit-level study provided a better understanding of the effect of unit work environment upon nursing practice and outcomes.