Increasing effectiveness of modeling

Modeling is the essence of the operations research study. Yet with the exception of rare instances does the model of the study realize its full potential benefits in the business world. In this treatise an attempt is made to familiarize the business world with the types of models that exist including their operational and functional attributes. In order to increase the model and or study effectiveness the essential elements in performance are expounded to illustrate the comprehensiveness required. In conclusion, the recognition that modeling is not a utopia and that many pitfalls exist is explored with recommendations made to diminish or eliminate the negative impact of these shortcomings.     

Managing the Risk of Uncertain Threshold Responses: Comparison of Robust, Optimum, and Precautionary Approaches

Many commentators have suggested the need for new decision analysis approaches to better manage systems with deeply uncertain, poorly characterized risks. Most notably, policy challenges such as abrupt climate change involve potential nonlinear or threshold responses where both the triggering level and subsequent system response are poorly understood. This study uses a simple computer simulation model to compare several alternative frameworks for decision making under uncertainty -- optimal expected utility, the precautionary principle, and three different approaches to robust decision making -- for addressing the challenge of adding pollution to a lake without triggering unwanted and potentially irreversible eutrophication. The three robust decision approaches -- trading some optimal performance for less sensitivity to assumptions, satisficing over a wide range of futures, and keeping options open -- are found to identify similar strategies as the most robust choice. This study also suggests that these robust decision approaches offer a quantitative, decision analytic framework that captures the spirit of the precautionary principle while addressing some of its shortcomings. Finally, this study finds that robust strategies may be preferable to optimum strategies when the uncertainty is sufficiently deep and the set of alternative policy options is sufficiently rich.     

From habitus to mouth: Language and class in Bourdieu's sociology of language

Theory and Society -     

Sports Involvement as Protection against Depressed Mood

Working within a risk and protection framework, this research brief examines the protective inà uence of team sports involvement on adolescent depressed mood. The objective was to understand whether sports involvement positively contributes to mental health independent of the effects of other known protective factors (parental and peer support); and whether it moderates the depressive effects of family, peer, and school‐based risk factors. Analyses focused on 1,036 high school‐aged youth interviewed at two time points. Regression analysis results indicated a signià cant association between team sports involvement and depressed mood among both males and females, which was reduced to insignià cance after controlling for the other protective factors. One interaction effect was observed: for females, but not males, team sports involvement was shown to protect against depressed mood associated with poor school performance (low grade point average). Thus, the role of sports involvement as a positive instrumental activity for females is discussed.     

Solutions to the Exploration/Exploitation Dilemma: Networks as a New Level of Analysis

This paper reviews the extant literature on the exploration/exploitation dilemma. Based on a systematic analysis of structural, behavioural, systemic and temporal solutions, the authors are able to show that the learning literature continues to struggle with the question of how exactly an organization can separate exploration and exploitation and at the same time enable necessary knowledge exchange and cooperation between these two notions. Paying closer attention to networks might enable future research to answer this question. In particular, a combination of structural aspects of networks and social ties has the potential to explain how the solutions currently on offer can be implemented successfully, how organizations can combine several of them, and how they can shift between them.     

Family planning program effects on contraceptive use in Morocco, 1992–1995

This study illustrates the use of panel data and a fixed-effects estimator to investigate the impact of family planning program inputs on contraceptive utilization in Morocco during the 1992–1995 period. By controlling the potential bias resulting from common unobserved determinants of program resource allocation decisions and program outcomes, the methodology helps overcome an important constraint to the use of non-experimental study designs in undertaking meaningful impact assessments. Data from a panel of women interviewed in both the 1992 and 1995 Morocco Demographic and Health Surveys were used in the study, along with program data from Service Availability Modules undertaken in conjunction with each survey round. The results indicate that changes in the family planning supply environment, in particular increased presence of nurses trained in family planning and the level of infrastructure at public clinics, played a significant role in the increased use of modern contraceptives during the study period.     

Did tax incentives play any part in increased giving?

Since 2000, increased taxation incentives along with other measures have been used by the government to encourage philanthropy in Australia. Since the new incentives were introduced, claimed gift tax deductions have increased. However, generally, donors are not aware of the new tax incentives for giving and in any case they report that their motivation for giving is not primarily, if at all, to obtain tax incentives. This article examines this paradox and seeks some possible explanations.