Supermodularity and the Comparative Statics of Risk

In this article, it is shown that a wide range of comparative statics results from expected utility theory can be extended to generalized expected utility models using the tools of supermodularity theory. In particular, a range of concepts of decreasing absolute risk aversion may be formulated in terms of the supermodularity properties of certainty equivalent representations of preferences.     

Can we Lend?: Communicating Interlibrary Loan Rights

At the 22nd Annual North Carolina Serials Conference, focused on “Collaboration, Community, and Connection,” Linda Blake and Hilary Fredette of West Virginia University presented, ““Can we Lend?”: Communicating Interlibrary Loan Rights,” reviewing their experiences collaborating across an academic library to achieve the best possible interlibrary loan e-journal access within the bounds of sometimes inscrutable licenses.     

The Use of Flexible Manufacturing Capacity in Pharmaceutical Product Introductions*

This work considers the value of the flexibility offered by production facilities that can easily be configured to produce new products. We focus on technical uncertainty as the driver of this value, while prior works focused only on demand uncertainty. Specifically, we evaluate the use of process flexibility in the context of risky new product development in the pharmaceutical industry. Flexibility has value in this setting due to the time required to build dedicated capacity, the finite duration of patent protection, and the probability that the new product will not reach the market due to technical or regulatory reasons. Having flexible capacity generates real options, which enables firms to delay the decision about constructing product‐specific capacity until the technical uncertainty is resolved. In addition, initiating production in a flexible facility can enable the firm to optimize production processes in dedicated facilities. The stochastic dynamic optimization problem is formulated to analyze the optimal capacity and allocation decisions for a flexible facility, using data from existing literature. A solution to this problem is obtained using linear programming. The result of this analysis shows both the value of flexible capacity and the optimal capacity allocation. Due to the substantial costs involved with flexibility in this context, the optimal level of flexible capacity is relatively small, suggesting products be produced for only short periods before initiating construction of dedicated facilities.     

Decision‐making in drug development using a composite definition of success

Evidence‐based quantitative methodologies have been proposed to inform decision‐making in drug development, such as metrics to make go/no‐go decisions or predictions of success, identified with statistical significance of future clinical trials. While these methodologies appropriately address some critical questions on the potential of a drug, they either consider the past evidence without predicting the outcome of the future trials or focus only on efficacy, failing to account for the multifaceted aspects of a successful drug development. As quantitative benefit‐risk assessments could enhance decision‐making, we propose a more comprehensive approach using a composite definition of success based not only on the statistical significance of the treatment effect on the primary endpoint but also on its clinical relevance and on a favorable benefit‐risk balance in the next pivotal studies. For one drug, we can thus study several development strategies before starting the pivotal trials by comparing their predictive probability of success. The predictions are based on the available evidence from the previous trials, to which new hypotheses on the future development could be added. The resulting predictive probability of composite success provides a useful summary to support the discussions of the decision‐makers. We present a fictive, but realistic, example in major depressive disorder inspired by a real decision‐making case.     

A nonparametric maximum likelihood approach for survival data with observed cured subjects,left truncation and right-censoring

We consider observational studies in pregnancy where the outcome of interest is spontaneous abortion (SAB). This at first sight is a binary ‘yes’ or ‘no’ variable, albeit there is left truncation as well as right-censoring in the data. Women who do not experience SAB by gestational week 20 are ‘cured’ from SAB by definition, that is, they are no longer at risk. Our data is different from the common cure data in the literature, where the cured subjects are always right-censored and not actually observed to be cured. We consider a commonly used cure rate model, with the likelihood function tailored specifically to our data. We develop a conditional nonparametric maximum likelihood approach. To tackle the computational challenge we adopt an EM algorithm making use of “ghost copies” of the data, and a closed form variance estimator is derived. Under suitable assumptions, we prove the consistency of the resulting estimator which involves an unbounded cumulative baseline hazard function, as well as the asymptotic normality. Simulation results are carried out to evaluate the finite sample performance. We present the analysis of the motivating SAB study to illustrate the advantages of our model addressing both occurrence and timing of SAB, as compared to existing approaches in practice.     

Applicant reactions and their consequences: review, advice, and recommendations for future research

Recent years have seen an abundance of research addressing applicant reactions to personnel recruitment and standard selection procedures. However, most of this research focuses on isolating the determinants of these reactions rather than on their consequences. For example, just because an individual perceives a selection procedure as unfair, does this actually have any impact on the organization? In an attempt to fill this void in the literature, the current paper focuses on the outcomes and consequences of applicant reactions to personnel selection procedures. Specifically, the current paper (1) reviews the extant research on the consequences of applicant reactions, (2) advances a summative model of existing theory and research, (3) provides recommendations to organizational leaders who are concerned about the impact of applicant reactions to their personnel selection procedures, and (4) discusses directions for future research that will better substantiate these recommendations given to organizational leaders.     

Success and Failure of MRP II Implementation

This paper assesses the reasons for the success or failure of manufacturing resource planning (MRPII) implementation projects. It begins by discussing the literature and research on success and failure of these systems and presents evidence from cases prepared by the authors. The paper is not concerned to prescribe ‘best practice’ for MRP implementation. The first section reviews the relevant literature and concludes that there is a divergence of opinion as to what constitutes success, raising questions on the usefulness of current methods of establishing whether implementation is successful. The latter section of the paper uses results from longitudinal (process) research carried out by the authors. This starts with a discussion of what counts for success. The discussion highlights the importance of understanding the full potential of MRPII in effecting change of organizational structures, cultures and practice. Several factors that contribute towards MRPII failure are next considered. Finally,‘big bang’style implementations, such as those recommended by the Ollie Wight organization, are most likely to be successful if the organization follows a strategic approach to planning. There also needs to be a high degree of fit between organizational structure, culture and the demands of the MRPII system.     

Estimation of Long-Term Risk from Canadian Uranium Mill Tailings

A methodology is presented for assessing the risk from Canadian uranium mill tailings piles. The methodology is based on the "set of triplets" concept and uses an event tree to identify various scenarios representing the performance of a pile over its 1,000-year design life. Compartment-type mathematical models are used to quantify the movement of hazardous substances through the environment. Numerical examples are given of both "level 1" (straight probabilistic) and "level 2" (probability of frequency) type analyses.     

Oral sex: varied behaviors and perceptions in a college population

Views and behaviors pertaining to oral sex have changed in recent years. This anonymous, online survey posed both old and new questions pertaining to oral sex among a college population. This study confirmed previous findings about virgins engaging in oral sex, but also found that women reported giving oral sex more often than receiving it from men. Oral sex was not only perceived as less intimate than intercourse, but more likely to be perceived as less intimate by women than men. Participants most frequently endorsed a committed relationship, but not a married relationship, for comfort in engaging in oral sex. Lastly, college students were more knowledgeable of the sexually transmitted infection risks of oral sex than how to actually protect themselves during oral sex. Additional analyses by gender and virginity were also performed to further understanding of the nuances amongst virgins and women and men.