Applications and Implementation

We propose an alternative solution to the discriminant problem, one that requires little more than a minimum familiarity with linear programming. The approach shows promise for eliminating the complexities of conventional statistical approaches without sacrificing the essential power of existing methods.     

A Stochastic Goal Program for Employee Scheduling*

Deterministic goal programs for employee scheduling decisions attempt to minimize expected operating costs by assigning the ideal number of employees to each feasible schedule. For each period in the planning horizon, managers must first determine the amount of labor that should be scheduled for duty. These requirements are often established with marginal analysis techniques, which use estimates for incremental labor costs and shortage expenses. Typically, each period in the planning horizon is evaluated as an independent epoch. An implicit assumption is that individual employees can be assigned to schedules with as little as a single period of work. If this assumption violates local work rules, the labor requirements parameters for the deterministic goal program may be suboptimal. As we show in this research, this well-known limitation can lead to costly staffing and scheduling errors. We propose an employee scheduling model that overcomes this limitation by integrating the labor requirements and scheduling decisions. Instead of a single, externally determined staffing goal for each period, the model uses a probability distribution for the quantity of labor required. The model is free to choose an appropriate staffing level for each period, eliminating the need for a separate goal-setting procedure. In most cases this results in better, less costly decisions. In addition, the proposed model easily accommodates both linear and nonlinear under- and overstaffing penalties. We use simple examples to demonstrate many of these advantages and to illustrate the key techniques necessary to implement our model. We also assess its performance in a study of more than 1,700 simulated stochastic employee scheduling problems.     

The Impact of a Structured-Argument Approach on Group Problem Formulation*

Despite advances in decision analysis and decision support systems, few formulaic procedures exist for undertaking problem formulation, particularly in group settings. This leaves managers with little procedural support for the important task of carefully structuring problems. In a laboratory experiment of 29 intact student teams, we contrasted two problem formulation methodologies: a structured argument approach (based on application of formal reasoning) and a group process approach (based on private idea generation prior to public sharing and evaluation of ideas). The structured argument approach took more time to use and failed to bring about more information search and equivocality reduction in group discussions. On the positive side, however, the structured argument approach led to a greater combination of both coverage of critical issues and consensus on those issues. Use of the structured argument approach also resulted in higher satisfaction with the problem definition and commitment to implementing results of the group meeting. Overall, the results reveal cost/benefit tradeoffs associated with developing argumentation-based procedures for problem formulation.     

Young people and caregivers' perceptions of an intervention program for children who deliberately light fires

A significant number of children and adolescents engage in deliberate fire setting, beyond the scope of curiosity and experimentation. Interventions developed to respond to the needs of such fire setters generally involve educational and/or psychosocial approaches. Research evaluating the effectiveness of these interventions is dominated by outcome studies which rely on recidivism rates determined by either official records or parent reports. There has however, been no process evaluation studies published. This study presents a process analysis which aimed to identify the strengths and weaknesses of a Fire Awareness and Intervention Program in New Zealand, from the perspectives of program consumers. Qualitative research methods were employed, with data being derived from in-depth interviews with young people and their parents/caregivers. The analysis indicated that (a) the FAIP was generally regarded as a positive experience, (b) practitioners' qualities of empathy and understanding are important for developing rapport with the young people and their parents, (c) education-based intervention tailored to the young person's age and developmental level is important, (d) educational resources need to be updated and used flexibly to respond appropriately to the age and developmental level of the young person, and (e) inter-agency and intra-agency relationships need to be developed and maintained, with formal arrangements for reciprocal referral systems developed in order to respond to the needs of the clients. The resulting implications for service providers, along with future research are discussed.     

A robust QTL mapping procedure

In quantitative trait linkage studies using experimental crosses, the conventional normal location-shift model or other parameterizations may be unnecessarily restrictive. We generalize the mapping problem to a genuine nonparametric setup and provide a robust estimation procedure for the situation where the underlying phenotype distributions are completely unspecified. Classical Wilcoxon–Mann–Whitney statistics are employed for point and interval estimation of QTL positions and effects.     

Life Course Changes in Smoking by Gender and Education: A Cohort Comparison Across France and the United States

Widening of educational disparities and a narrowing female advantage in mortality stem in good part from disparities in smoking. The changes in smoking and mortality disparities across cohorts and countries have been explained by an epidemic model of cigarette use but are also related to life course changes. To better describe and understand changing disparities over the life course, we compare age patterns of smoking in three cohorts and two nations (France and the US) using smoking history measures from the 2010 French health barometer (N = 20,940) and the 2010 US National Health Interview Survey Sample Adult File (N = 20,444). The results demonstrate statistically significant widening of gender and educational differences from adolescence to early and middle adulthood, thus accentuating the disparities already emerging during adolescence. In addition, the widening disparities over the life course have been changing across cohorts: age differences in educational disparities have grown in recent cohorts (especially in France), while age differences in gender disparities have narrowed. The findings highlight the multiple sources of inequality in smoking and health in high-income nations.