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There are over 90,000 patients in the United States waiting for a kidney transplant. Under the current allocation policy, the vast majority of deceased organs are allocated locally. This causes significant disparities in waiting times and access to transplant across different geographical areas. To ameliorate this inequity, we propose an operational solution that offers affordable jet services (OrganJet) to patients on the transplant waiting list, allowing them to list in multiple different, and possibly very distant, donation service areas (DSAs) of their choosing. First, using a fluid approximation, we formulate the patients' problem of choosing a location to multiple list as a selfish routing game in which each patient tries to minimize his 'congestion cost,' i.e., maximize his life expectancy. Through a combination of numerical, simulation, and analytical results, we show that multiple listing can lead to a significant improvement in geographic equity. In the special case when sufficiently many patients can multiple list, the geographic inequity disappears. Moreover, the supply of deceased donor organs increases under multiple listing, leading to more transplants and saved lives. We also consider a diffusion approximation and study the resulting multiple-listing game. The equilibrium outcome under the diffusion approximation is a second-order perturbation of that under the selfish routing formulation. In particular, the geographic equity metric, waiting times, and probabilities of receiving a transplant at various DSAs in equilibrium are second-order perturbations of those predicted by the selfish routing equilibrium. Hence, the analysis under the diffusion approximation also supports the finding that multiple listing leads to an improvement in geographic equity. In addition, restricting attention to the special case of sufficiently many patients multiple listing leads to an explicit characterization of the equilibria, which in turn yields additional structural insights. Last, we undertake a simulation study that supports aforementioned findings. History: Accepted by Assaf Zeevi, stochastic models and simulation. Supplemental Material: The online appendix is available at https://doi.org/10.1287/mnsc.2016.2487. Keywords: stochastic model applications * queues * diffusion models * healthcare * transplant * game theory * selfish routing games * geographic disparity, 1. Introduction Steve Jobs received a liver transplant in Tennessee in March 2009, although he was first put on the transplant waiting list in California, where he lived. Because of [...]

We model the decision-making process of callers in call centers as an optimal stopping problem. After each waiting period, a caller decides whether to abandon a call or continue to [...]

This paper analyzes the United States Medicare hospice reimbursement policy. The existing policy consists of a daily payment for each patient under care with a global cap of revenues accrued during the Medicare year, which increases with each newly admitted patient. We investigate the hospice's expected profit and provide reasons for a spate of recent provider bankruptcies related to the reimbursement policy; recommendations to alleviate these problems are given. We also analyze a hospice's incentives for patient management, finding several unintended consequences of the Medicare reimbursement policy. Specifically, a hospice may seek short-lived patients (such as cancer patients) over patients with longer expected lengths of stay. The effort with which hospices seek out, or recruit, such patients will vary during the year. Furthermore, the effort they apply to actively discharge a patient whose condition has stabilized may also depend on the time of year. These phenomena are unintended and undesirable but are a direct consequence of the Medicare reimbursement policy We propose an alternative reimbursement policy to ameliorate these shortcomings. Key words: healthcare; government: regulations; fluid analysis; simulation History: Received September 27, 2010; accepted June 5, 2012, by Christian Terwiesch, operations management. Published online in Articles in Advance December 10, 2012., 1. Introduction and Problem Motivation Hospices are healthcare providers that cater to patients in the end phases of their lives who choose to undertake palliative care in lieu of further [...]

The revenue management literature for queues typically assumes that providers know the distribution of customer demand attributes. We study an observable M/M/1 queue that serves an unknown proportion of patient [...]

A waste-to-energy firm that recycles organic waste with energy recovery performs two environmentally beneficial functions: it diverts waste from landfills and it produces renewable energy. At the same time, the [...]

We consider outsourcing in two important service settings: call center and order fulfillment operations. An important factor in both is the inherent economies of scale. Therefore, we advance a unifying [...]

We consider a continuous-time, rate-based model of network revenue management. Under mild assumptions, we construct a simple ζ-optimal bid-price control, which can be viewed as a perturbation of a bid-price control in the classical sense [Williamson, E. L. 1992. Airline network seat control. Ph.D. thesis, MIT, Cambridge, MA]. We show that the associated bid-price process forms a martingale and the corresponding booking controls converge in an appropriate sense to an optimal control as ζ tends to 0. Moreover, we show that there exists an optimal generalized bid-price control, where the bid-price process forms a martingale and is used in conjunction with a capacity usage limit process. We also discuss its connection to the bid-price controls in the classical sense and sufficient conditions for the (near) optimality of the latter. Key words: bid-price controls; network revenue management; martingales MSC2000 subject classification: Primary: 90B99, 60G44; secondary: 93E03 OR/MS subject classification: Primary: stochastic model applications, network models; secondary: infinite dimensional programming History: Received January 20, 2007; revised April 8, 2008, and January 14, 2009. Published online in Articles in Advance October 7, 2009. DOI 10.1287/moor.1090.0411, 1. Introduction. Network revenue management problems arise naturally in airline, railway, cruise-line, and hotel revenue management, more generally, whenever, customers buy bundles of resources under various terms and conditions. In [...]

We investigate how dynamic resource substitution in service systems impacts capacity requirements and responsiveness. Inspired by the contrasting network strategies of FedEx and United Parcel Service (UPS), we study when two service classes (e.g., express or regular) should be served by dedicated resources (e.g., air or ground) or by an integrated network (e.g., air also serves regular). Using call center terminology, the question is whether to operate two independent queues or one N-network. We present analytic expressions for the delay distributions and the value of network integration through partial resource pooling. These show how the value of network integration depends on service quality (speed and reliability of service) and demand characteristics (volume averages and covariance matrix). Our results suggest that network integration is of little value and operating dedicated networks is a fine strategy if the firm primarily serves express requests with high reliability and if the correlation with regular requests is not strongly negative. In contrast, network integration offers significant gains for firms serving primarily regular requests, almost independent of correlation. Our analysis provides the intuition behind these findings in terms of three main drivers of integration value: arrival pooling, the substitution effect, and the correlation effect. Key words: network integration strategy; quality of service; flexible technology; N-network, skill-based routing; queueing History: Accepted by Michael Fu, stochastic models and simulation; received January 26, 2006. This paper was with the authors 1 year and 2 months for 2 revisions. Published online in Articles in Advance October 7, 2008., 1. Introduction and Summary In this paper, we study the value of dynamic resource substitution in service systems. Using a stylized analytic model of a firm that serves two separate [...]

We study a service facility in which the system manager dynamically controls the arrival and service rates to maximize the long-run average value generated. We initially consider a rate-setting problem where the service facility is modeled as an M/M/1 queue with adjustable arrival and service rates and solve this problem explicitly. Next, we use this solution to study a price-setting problem, where customers are utility maximizing and price- and delay-sensitive, and the system manager chooses state-dependent service rates and prices. We find that the optimal arrival rate is decreasing and the optimal service rate is increasing in the number of customers in the system; however, the optimal price need not be monotone. We also show that under the optimal policy, the service facility operates as one with a finite buffer. Finally, we study a numerical example to compare the social welfare achieved using a dynamic policy to that achieved using static policies and show the dynamic policy offers significant welfare gains. Key words: stochastic models of service systems; dynamic control; delay-sensitive customers, 1. Introduction In the highly competitive business environment prevalent today, the ability to dynamically control cost and value factors can give an operation a significant competitive advantage. The control of [...]

The Stochastic Models and Simulation Department seeks to publish work that contributes to the modeling, analysis, or simulation of stochastic systems, broadly construed, through advances in methodology and/or application. These [...]

The continued success of Manufacturing & Service Operations Management (M&SOM) relies on the support of authors and reviewers. On behalf of M&SOM, I would like to express my sincere appreciation [...]

The continued success of Manufacturing & Service Operations Management (M&SOM) relies on the support of authors and reviewers. On behalf of M&SOM, I would like to express my sincere appreciation [...]

The continued success of Manufacturing & Service Operations Management (M&SOM) relies on the support of authors and reviewers. On behalf of M&SOM, I would like to express my sincere appreciation [...]

Manufacturing & Service Operations Management (M&SOM) formally thanks the guest editors and reviewers, who provided expert counsel and guidance on a voluntary basis. Through their efforts, the journal was able [...]

Manufacturing & Service Operations Management (M&SOM) formally thanks the guest associate editors and reviewers, who provided expert counsel and guidance on a voluntary basis. Through their efforts the journal was [...]

M&SOM formally thanks the guest associate editors and reviewers, who provided expert counsel and guidance on a voluntary basis. Through their efforts the journal was able to provide submitting authors [...]