An Integrated Risk Model of a Drinking-Water – Borne Cryptosporidiosis Outbreak

A dynamic risk model is developed to track the occurrence and evolution of a drinking-water–borne cryptosporidiosis outbreak. The model characterizes and integrates the various environmental, medical, institutional, and behavioral factors that determine outbreak development and outcome. These include contaminant delivery and detection, water treatment efficiency, the timing of interventions, and the choices that people make when confronted with a known or suspected risk. The model is used to evaluate the efficacy of alternative strategies for improving risk management during an outbreak, and to identify priorities for improvements in the public health system. Modeling results indicate that the greatest opportunity for curtailing a large outbreak is realized by minimizing delays in identifying and correcting a drinking-water problem. If these delays cannot be reduced, then the effectiveness of risk communication in preemptively reaching and persuading target populations to avoid exposure becomes important.     

Predicting Emergency Evacuation and Sheltering Behavior: A Structured Analytical Approach

We offer a general approach to predicting public compliance with emergency recommendations. It begins with a formal risk assessment of an anticipated emergency, whose parameters include factors potentially affecting and affected by behavior, as identified by social science research. Standard procedures are used to elicit scientific experts' judgments regarding these behaviors and dependencies, in the context of an emergency scenario. Their judgments are used to refine the model and scenario, enabling local emergency coordinators to predict the behavior of citizens in their area. The approach is illustrated with a case study involving a radiological dispersion device (RDD) exploded in downtown Pittsburgh, PA. Both groups of experts (national and local) predicted approximately 80-90% compliance with an order to evacuate workplaces and 60-70% compliance with an order to shelter in place at home. They predicted 10% lower compliance for people asked to shelter at the office or to evacuate their homes. They predicted 10% lower compliance should the media be skeptical, rather than supportive. They also identified preparatory policies that could improve public compliance by 20-30%. We consider the implications of these results for improving emergency risk assessment models and for anticipating and improving preparedness for disasters, using Hurricane Katrina as a further case in point.     

Alternative Models for Antecedents and Outcomes of Work Centrality and Job Satisfaction of High-Tech Personnel

Alternative causal models were developed,relating Work Centrality and Job Satisfaction toantecedents and outcomes. The antecedents examined weredemographics and need for achievement, and the outcomes included performance, wages, organizationalcommitment, and career planning. The models were testedusing data of Israeli high-tech personnel. Resultsindicated that organizational commitment, careerplanning, and wages were significantly affected by workcentrality, while performance was positively butnonsignificantly related to it. While all models provedto be acceptable, the best model posited JobSatisfaction as an antecedent rather than an outcome of WorkCentrality. It also revealed the importance ofdemographics for outcomes. Implications arediscussed.     

Employability: a substitute for loyalty?

Within the theme of contemporary innovative work arrangements and new psychological contracts, a new buzzword has been introduced: employability. This paper offers an analytical assessment of the idea, how it came into life, and the prospects of its adoption by organizations. A critical review is followed by a field study conducted to examine reaction to the idea, based on exploratory, in-depth interviews with HR directors. Based on a theoretical and management development perspective, as well as logical analysis, the paper concludes that the idea is flawed. Views expressed were mostly negative. It is implied that, though the concept of employability is beneficial for individuals, it would be unacceptable for organizations to 'sell' it to employees as a replacement for long-term commitment or loyalty and trust-based relationships.     

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.     

What Number is “Fifty‐Fifty”?: Redistributing Excessive 50% Responses in Elicited Probabilities

Studies using open-ended response modes to elicit probabilistic beliefs have sometimes found an elevated frequency (or blip) at 50 in their response distributions. Our previous research suggests that this is caused by intrusion of the phrase "fifty-fifty," which represents epistemic uncertainty, rather than a true numeric probability of 50%. Such inappropriate responses pose a problem for decision analysts and others relying on probabilistic judgments. Using an explicit numeric probability scale (ranging from 0-100%) reduces thinking about uncertain events in verbal terms like "fifty-fifty," and, with it, exaggerated use of the 50 response. Here, we present two procedures for adjusting response distributions for data already collected with open-ended response modes and hence vulnerable to an exaggerated presence of 50%. Each procedure infers the prevalence of 50s had a numeric probability scale been used, then redistributes the excess. The two procedures are validated on some of our own existing data and then applied to judgments elicited from experts in groundwater pollution and bioremediation.     

Risk Perception and Communication Unplugged: Twenty Years of Process1

Over the past twenty years, risk communication researchers and practitioners have learned some lessons, often at considerable personal price. For the most part, the mistakes that they have made have been natural, even intelligent ones. As a result, the same pitfalls may tempt newcomers to the field. This essay offers a personal (even confessional) history of the field over this period. It identifies a series of developmental stages. Progress through the stages involves consolidating the skills needed to execute it and learning its limitations. Knowing about their existence might speed the learning process and alert one to how much there still is to learn.     

The single-period inventory problem: Extension to random yield from the perspective of the supply chain

A special form of the single-period inventory problem (newsvendor problem) with a known demand and stochastic supply (yield) is studied. A general analytic solution for two types of yield risks, additive and multiplicative, is described. Numerical examples demonstrate the solutions for special cases of uniform distribution yield risks. An analysis of a two-tier supply chain of customer and producer reveals that the customer may find it optimal to order more than is needed, since a larger order increases the producer's optimal production quantity.