Elsevier

Omega

Volume 38, Issues 3–4, June–August 2010, Pages 157-166
Omega

A location–allocation model for service providers with application to not-for-profit health care organizations

https://doi.org/10.1016/j.omega.2009.08.001Get rights and content

Abstract

In this paper, we develop and solve a model for the location and allocation of specialized health care services such as traumatic brain injury (TBI) treatment. The model is based on and applied to one of the Department of Veterans Affairs’ integrated service networks. A cost minimization model with service proportion requirements is solved using simulated annealing. Large instances of the model with 100 candidate medical center locations and 15 open treatment units are solved in about 1000 s. In order to test the real-world applicability of our model, an extensive managerial experiment is conducted using data derived from our health care setting. In this experiment, the effects of three critical factors: (1) degree of centralization of services, (2) the role of patient retention as a function of distance to a treatment unit, and (3) the geographic density of the patient population are investigated with respect to the important trade-off between the cost of providing service and the need to provide such service. Our analysis shows that all three factors of the experiment are both relevant and useful to decision-makers when selecting locations for their services.

Introduction

At the beginning of the 21st century, health care remains one of the areas of crucial concern for millions of Americans. As evidence, it may be noted that obtaining and paying for high-quality health care was a major topic of debate in both the 2004 and 2008 presidential elections. While the United States is fortunate in possessing the world's finest medical facilities and technologies, it is well-known that health care costs are rapidly spiraling upward, currently constituting some 15% of national spending [1].

Health care providers are pressured by two conflicting aspects of the public debate on health issues. On one hand, it is clear that Americans value the quality of their health care facilities, treatments, and options. On the other hand, much to the consternation of the American public, the continuously rising cost of health care is reflected in ever-increasing health care insurance premiums, which remain a significant expense for most households. At a time when medical procedures, new technologies, and drugs are highly developed and consequently very expensive, the pressure to control costs is affecting the operations of health care organizations in general and hospitals in particular. While the public debate about health care will not diminish, health care providers such as hospitals have no choice at present but to become as efficient as possible in all aspects of their operations [2], [3].

This study is motivated by the need for effective delivery of specialized health services at the Department of Veterans Affairs (VA), the primary service organization dedicated to the care and well-being of American veterans. In particular, this study is based upon a funded research project that investigated the optimal location of traumatic brain injury (TBI) treatment units for VA medical centers. As a not-for-profit service organization, the VA has to define optimality using a multi-objective approach where both controlling the cost of providing care and determining the level and extent of the care provided (i.e., access and availability) are equally important goals to pursue.

This paper is organized as follows. Section 2 provides the motivation and literature review germane to our research. Section 3 describes our optimization model and defines the relevant decision variables and model coefficients. Section 4 describes our solution methodology for the optimization model while Section 5 provides the results of a rigorous computational testing of the model. Section 6 applies our model in a real-world experimental setting based upon our work with the VA. Last, concluding remarks and future research directions are given in Section 7.

Section snippets

Motivation and literature review

Location–allocation models seek to simultaneously determine optimal facility locations and the assignment of customers to the selected facilities. The research literature in facility location is vast. For the interested reader, a comprehensive review of general facility location models and the methods used to solve them may be found in Love et al. [4] and Cornuéjols et al. [5]. Location–allocation models have been extensively applied in health care settings including locating hospitals in rural

The optimization model

The purpose of the research presented here is to develop a framework for mathematically analyzing the issues related to the location of specialized health care services for the VA. The optimization model presented in this section is based on the needs of the VA as a not-for-profit service organization. It includes two primary criteria: (1) the VA's cost of providing service and (2) the service rate provided to the VA's patients. The cost of service is made up of fixed and variable treatment

Solution methodology

Model (VA) contains a large number of binary variables and also a large number of constraints. For example, if our model were to be applied on a national scale, the resulting application would contain approximately 43,000 districts at the ZIP code level and 155 possible treatment unit locations corresponding to the current total number of medical centers within the VA. The presence of the 0–1 variables and the potentially large model size puts the model into the category of combinatorial

Computational experiment

The computational experiment was carried out on a Compaq Presario desktop computer with 512 MB of memory running at 2.2 GHz on an AMD Athlon processor. As stated earlier, Model (VA) is NP-complete [14] and the solution times tend to increase exponentially when searching for the optimal solution with general-purpose solvers such as Lingo 7. In our investigations, we found that solving problems with 25 candidate medical center locations, 5 open treatment units, and 40 patient districts (the same

Managerial experiment and implications

Service organizations such as the VA are under great pressure along a number of conflicting fronts. While some of these are well documented, others are more subtle and related to the internal dynamics of a particular organization. In fact, some of the criteria might not even be explicitly acknowledged by an organization but nevertheless exert real influence on the decision-making process (in this case, with regard to location and capacity issues). Our work with some of these organizations, not

Conclusion

In this paper, we have developed a model for the location of specialized health care services such as TBI treatment units. We have applied this model to data based on one of the VA's integrated service networks. The model incorporates two primary criteria for the location of treatment units: (1) a cost minimization objective that includes relevant costs such as treatment, transportation, labor, and fixed costs, and (2) a minimum service proportion requirement that is consistent with the VA's

Acknowledgments

This work was funded by the Department of Veterans Affairs (VA) Rehabilitation Research and Development (RR&D) Service through the VA RR&D Rehabilitation Outcomes Research Center at the Malcolm Randall VA Medical Center in Gainesville, Florida (Project #B2610R, W. Bruce Vogel, Principal Investigator).

Disclaimer: The views expressed here are those of the researchers and do not necessarily reflect the views of the Department of Veterans Affairs.

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