Analysis and Management of Periodic Review,Order‐Up‐To Level Inventory Systems with Order Crossover

In this article, we investigate the (R, S) periodic review, order‐up‐to level inventory control system with stochastic demand and variable leadtimes. Variable leadtimes can lead to order crossover, in which some orders arrive out of sequence. Most theoretical studies of order‐up‐to inventory systems under variable leadtimes assume that crossovers do not occur and, in so doing, overestimate the standard deviation of the realized leadtime distribution and prescribe policies that can inflate inventory costs. We develop a new analytic model of the expected costs associated with this system, making use of a novel approximation of the realized (reduced) leadtime standard deviation resulting from order crossovers. Extensive experimentation through simulation shows that our model closely approximates the true expected cost and can be used to find values of R and S that provide an expected cost close to the minimum cost. Taking account of, as opposed to ignoring, crossovers leads, on average, to substantial improvements in accuracy and significant cost reductions. Our results are particularly useful for managers seeking to reduce inventory costs in supply chains with variable leadtimes.     

Beyond Spatial Models: A New Perspective on American Operational Ideology Using Latent Class Analysis

Analyses of operational ideology—the pattern of correlations between different political attitudes—in the American public generally assume “spatial” models of ideology. Using Latent Class Analysis, we relax many of these assumptions by treating operational ideology as a latent categorical variable and analyze the changing structure of American operational ideology between 2004 and 2020. We find that some Americans during this period held consistently liberal or conservative views and were well sorted into the “correct” political parties. For other Americans, however, we observe complex and shifting relationships between partisanship and economic, moral, and racial attitudes. We find that Racial Justice Communitarians consistently prefer to identify as Democrats, while Nativist Communitarians and Libertarians both tended to identify with whatever party won the most recent presidential election. Future studies of operational ideology should be wary of simplifying assumptions that obscure important dynamics in American politics.     

Directed Matching and Monetary Exchange

We develop a model of monetary exchange where, as in the random matching literature, agents trade bilaterally and not through centralized markets. Rather than assuming they match exogenously and at random, however, we determine who meets whom as part of the equilibrium. We show how to formalize this process of directed matching in dynamic models with double coincidence problems, and present several examples and applications that illustrate how the approach can be used in monetary theory. Some of our results are similar to those in the random matching literature; others differ significantly.     

ONE APPROACH TO REALLOCATING INSTRUCTIONAL RESOURCES: THE HOUSTON MODEL

In this paper a model for deciding which instructional departments should receive and surrender new or reallocatable resources is developed. It combines a two-dimensional assessment of resource needs based on instructional characteristics and the academic priority of the department to arrive at resource allocation priorities. Unusual features of the model are its reliance on judgments of departmental centrality to institutional mission as the discriminating variable in ascribing academic priorities and the careful avoidance of “halo effects” through independent assessment of resource needs and academic priorities. The model is sensitive enough to discriminate between competing claims for scarce resources while retaining a simplicity of logic that makes its mechanics understandable to those with little grounding in the decision sciences.     

Hidden champions: Exploring supportive family relationships of youth experiencing homelessness

The relationships that youth experiencing homelessness (YEH) have with supportive family members (i.e. those who provide them with social support) may be protective against risk behaviours and buffer adverse health outcomes. However, little is known about the nature of YEH's supportive family relationships and the type of social support that these family relationships offer them. Thus, we conducted in-depth interviews with 30 YEH to examine the type of social support received from family relationships and to explore the social dynamics of these relationships. We found that many YEH not only continued to maintain relationships with family members after becoming homeless but also received emotional and/or instrumental support from these family members. Beyond providing this type of social support, family members served as a source of motivation for these youth. Additionally, YEH contributed to their family relationships and gained a sense of connectedness in return. Lastly, we found that YEH's family support was influenced by their family circumstances and their need for autonomy. Collectively, our findings suggest there may be a need for interventions designed to strengthen relationships with supportive family members among YEH, who may derive multiple positive benefits from relating with the ‘hidden champions’ in their lives.