Global sensitivity analysis of stochastic computer models with joint metamodels

The global sensitivity analysis method used to quantify the influence of uncertain input variables on the variability in numerical model responses has already been applied to deterministic computer codes; deterministic means here that the same set of input variables always gives the same output value. This paper proposes a global sensitivity analysis methodology for stochastic computer codes, for which the result of each code run is itself random. The framework of the joint modeling of the mean and dispersion of heteroscedastic data is used. To deal with the complexity of computer experiment outputs, nonparametric joint models are discussed and a new Gaussian process-based joint model is proposed. The relevance of these models is analyzed based upon two case studies. Results show that the joint modeling approach yields accurate sensitivity index estimators even when heteroscedasticity is strong.     

Service Patterns of Adult Survivors of Childhood Versus Adult Sexual Assault/Abuse

This analysis compared the characteristics and service patterns of adult survivors of childhood sexual assault/abuse and adult survivors of adult sexual assault/abuse. Utilizing data from sexual assault crisis centers serving survivors in a Midwestern state over a six year period and controlling for revictimization, we describe and compare the demographic characteristics, referral sources, and service patterns of the two groups. Results indicate that paths into service differ for the two groups. Furthermore, adult survivors of childhood sexual assault/abuse obtain significantly more hours of service and service contacts on average than adult survivors of adult sexual assault/abuse. Implications for policy and practice are discussed.     

Optimal age of retirement and population growth

The purpose of this paper is to study intergenerational optimal resources sharing when the social planer can choose the retirement age in addition to consumptions and investment. We use the extension of the Diamond analysis by Hu [1979] that incorporates endogenous retirement age. We found that the optimal retirement age is an increasing function of the population growth rate if the elasticity of substitution of old agents' labor for young agents' labor is lower than one. In the millian case, when the size of a population does not matter, and when the elasticity of substitution of old agents' labor for young agents' labor is strictly higher than one, the optimal retirement age is a decreasing function of the population growth rate. In the benthamite case, the change in the optimal retirement age is indeterminate. Received: 19 February 1999/Accepted: 27 February 2001 All correspondence to Bertrand Crettez. We would like to thank Jean-Pierre Vidal for very helpful comments on an earlier draft. An anonymous referee provided insightful comments on a previous version of this paper. Responsible editor: Alessandro Cigno.     

Creating competencies through collaboration:: The case of EUREKA R&D consortia

This article discusses the originality of European EUREKA consortia. Formed at the initiative of member firms, these consortia generally adopt a decentralised structure. Their main purpose is to conduct applied research, with the ultimate goal of exploiting its commercial opportunities. The consortia strive to ensure collaboration among firms in different countries, and at times, from different industries. Examining the management of R&D consortia, this article focuses primarily on the creation of new knowledge and competencies and on the benefits that member firms can reap from collaboration. Based on 20 interviews with project managers, the article brings to light two main observations: (1) the leader's positioning is a determining factor, and (2) a perfect balance between the firm's technological development and the consortium's strategic orientation facilitates the acquisition of competencies.     

Does Part-Time Mothering Help Get a Job? The Role of Shared Custody in Women’s Employment

Though child shared physical custody arrangements after divorce are much more frequent and parents who use it more diverse in many European countries, little is known about their economic consequences for parents. By relaxing family time constraints, does shared custody help divorced mothers return to or stay on work more easily? Since lone mothers are one of the least-employed groups, and they face high unemployment rates, the type of child custody arrangement adopted after divorce is of particular interest for their employability. This article analyses to what extent the type of child custody arrangement affects mothers’ labour market patterns after divorce.Using a large sample of divorcees from an exhaustive French administrative income tax database, and taking advantage of the huge territorial discrepancies observed in the proportion of shared custody, we correct for the possible endogeneity of shared custody. Results show that not repartnered mothers with shared custody arrangements are 24 percentage points more likely to work one year after divorce compared to those having sole custody, while no significant effect is found for repartnered mothers. Among lone mothers, we also highlight huge heterogeneous effects: larger positive effects are observed for previously inactive women, for those belonging to the lowest income quintiles before divorce, for those with a young child, and for those who have three or more children. Thus, shared physical custody arrangements may reduce work–family conflict by diminishing childcare expenses and enlarge the possibilities to find a suitable job because of more relaxed time constraints for lone mothers.     

“The Panhandle is Different than the Peninsula”: How Rural Colleges in Florida Implemented Education Reform

When it comes to the creation of higher education policy, state legislators are challenged with addressing the diverse academic needs of college students enrolled across a spectrum of institutions. In this paper, we explore how 203 individuals at five rural-serving colleges in Florida engaged in state-wide developmental education (DE) reform using the theoretical framework of “situated cognition.” Specifically, we ask whether the colleges implemented DE reform in unique ways that may have differed from their non-rural counterparts and what their rationale was for doing so. Our work indicates that institutional culture and capacity generated a combination of strengths and constraints in how reform played out in a rural context. In some ways, a rural-serving identity made colleges more flexible and better able to adjust their advising and curricular structures to comply with the mandates of SB 1720. But in other ways, rural-serving institutions lacked the resources necessary to adequately support students and campus personnel through this dramatic transition toward new ways of providing DE. In looking toward the passage and implementation of future education reform, we call upon policymakers to consider more deeply the design of policies to ensure they support rural and non-rural colleges alike.     

A framework for production control in health care organizations

The paper presents a hierarchical framework for production control of hospitals which deals with the balance between service and efficiency, at all levels of planning and control. The framework is based on an analysis of the design requirements for hospital production control systems. These design requirements are translated into the control functions at different levels of planning required for hospital production control. The framework consists of five levels of planning and control: patient planning and control, patient group planning and control, resources planning and control, patient volumes planning and control and strategic planning, though this last level does not make part of production control as such. Each of the levels of the framework is further elaborated in terms of the decisions made regarding patient flows and resources, and the co-ordination of the different planning levels. Implications of the framework are discussed by describing some points where current practice deviates from assumptions made in our approach. Recommendations for future research and development of the planning framework are formulated.     

Polarization or “Squeezed Middle” in the Great Recession?: A Comparative European Analysis of the Distribution of Economic Stress

This paper analyses variation in the impact of the Great Recession on economic stress across income classes for a range of advanced European countries. Our analysis shows Iceland, Ireland and Greece to be quite distinctive in terms of increases in their multidimensional income, material deprivation and economic stress profiles. Between 2008 and 2012 these countries moved from being predictably located within anticipated welfare regimes to becoming clear outliers. For this set of counties, each of which was exposed to different but severe forms of economic shock, trends in income class polarisation versus middle class squeeze were variable. Each exhibited substantial increases in levels of economic stress. However, changes in the pattern of income class differentiation were somewhat different. In Iceland a form of middle class squeeze was observed. For Ireland income class polarization did not exclude middle class squeeze. Greece came closest to fitting the polarization profile. Changes in the distribution of household equivalent income had no effect on stress levels once the impact of material deprivation was taken into account. Changes in levels of material deprivation played a significant role in accounting for changing stress levels but only for the three lowest income classes. These findings bring out the extent to which the impact of the Great Recession on the distribution of economic stress across classes varied even among the hardest-hit countries. They also serve to highlight the advantages of a multidimensional approach that goes beyond reliance on income in seeking to understand the impact of such shocks.     

Design requirements for health care production control systems

This paper addresses the issue of determining design requirements for production control in health care organizations, with a restriction to the internal production control of hospitals. Hospital management has limited possibilities to control hospital production, as hospital production processes are driven by medical specialists who, however, do not manage that process. We consider therefore the hospital as a virtual organization, consisting of a number of relatively independent businesses in a common framework. Each business unit functions as a focused factory for a range of more or less homogeneous products. Production control principles can be applied to each of these businesses, but not to the system as a whole. A number of elements from classical production control theory can be also applied to health care, i.e. the use of decoupling points, the bottleneck-oriented approach, and the operational control between production and market. However, important factors that need to be considered in health production control are that often specifications on quality are not available at the start of the process, and that there is strong interaction between the patient and the process. Our conclusion is that a dedicated framework for approaching hospital production control is necessary. The specific characteristics of hospital care and its state of production control development are the main arguments for this dedicated framework.