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Public Utility Model EMS

From their inception, public utility model (PUM) EMS systems have been a subject of controversy. Separating facts from hype can be challenging unless one has an understanding of how the PUM is designed, and more important, why certain features were incorporated into the system’s structure.

PUM: Patient’s Viewpoint

In 1972, researchers and scientists at the University of Oklahoma’s Center for Economic and Management Research (CEMR) met to study emergency medical services. Team member Jack Stout had directed the private ambulance EMS demonstration project for the federal government. The project had not performed as well as some of the others, and Stout wanted to know why.

Wanting to design an effective EMS system, the academics began by researching the ambulance industry and EMS. The group included members with “doctoral-level credentials in economics, organizational psychology, operations research, finance and accounting.”1 The interdisciplinary team conducted an extensive literature review, then conducted site visits to observe five systems that were operating well without federal or local tax subsidies and five that were subsidized.2

The federal government was leading an effort to upgrade EMS because of well-documented problems in ambulance service and emergency care. The research conducted by CEMR examined response time performance, levels of service and efficiency.

Once the research was completed, CEMR set about designing an ideal EMS system model, making patient care its highest priority, followed by financial stability and a professional work environment for field personnel. Many, then and now, assume that all EMS systems are designed with patient care as their highest priority, but this is not so.3 Following are the priorities that guided the team in designing the system:1

Patient Care

The model would deliver the highest levels of care and specifically avoid call screening (refusing service to telephone callers, which several large systems had tried with some well-publicized failures); transport refusals (crews refusing to transport patients from the scene to the hospital); and “hand-offs to BLS crews.” There are systems today that refuse service to certain patients. Rather than attempt to sort patients and run the risk of leaving seriously ill patients behind, the planners designed the PUM to transport all persons who asked for service.

Financial Stability

The model would create financial stability through efficiency and diversifying income sources to fund clinical care, regardless of changes in the economy.

Professional Environment

The model would provide a professional work environment for medics, EMTs, dispatchers and other support staff who are needed to deliver this level of care.

Restore Competition

The model would embrace the idea that no organization should be allowed to provide service without earning that right through competition.


The model would guarantee that rate-payers and taxpayers got full value for their money.

These priorities were not based upon science—they were value judgments. There is no way to prove that an EMS system should be designed with patient care as its highest priority any more than it is possible to prove that it should be designed for the comfort of its workers or the business interests of the organizations providing care. However, it is possible to look at an EMS system and determine whose interests are being served at the expense of others. Most EMS professionals believe patient care should be the highest priority of any system, but there seems to be a lot of disagreement about what exactly that means in terms of design features.

Economist’s Discovery

After studying the electric utility industry, an economist with the CEMR group noticed a number of similarities between the utility industry and EMS. Two characteristics were new and far-reaching in their implications:

Natural Monopoly

The most significant discovery was that the ambulance industry “exhibited all the classic characteristics of an economic natural monopoly.”1 In economics, a “natural monopoly” is an industry “whose market output is produced at the lowest cost when production is concentrated in the hands of a single firm.”4 This is true in the ambulance industry because, as the team found, there are dramatic economies of scale. The team saw that average costs declined as the population being served increased.1 The implication of this finding was that the most efficient system design would use a single provider.

Peak Demand

The team also found that the ambulance industry, like the electric utility industry, experienced periods of peak demand. Electricity usage varies by hour of day, day of week and season. The team discovered that graphs of ambulance calls also had peaks and valleys; that the cities studied each had unique patterns of demand use; and that these patterns were predictable in larger populations.1

The team named its ideal EMS system the “Public Utility Model,” recognizing that EMS had many of the same characteristics of a public utility. Also implicit in the name was the fact that this utility should be operated as a “public” entity because of the nature of the service and its role in supporting public safety.

Clinical Features

The team then set about designing its ideal system based upon the clinical priorities it had established. These features included all ALS, full service, and no call screening or provider-initiated refusals. The rationale for these features is described below.


The team faced the question of whether it could safely design a system that categorized patients into ALS and BLS categories. The team found that there was a risk of error when dispatchers, EMTs or paramedics attempted to determine which patients require ALS and BLS, or which patients could safely be denied higher levels of care. The conclusion drawn was that the way to eliminate that risk was to provide every patient with the highest level of care possible.

All things being equal, it seems the EMS community would agree on the benefit to patients of ALS vs. BLS-trained providers; however, there seems to be debate—much of it tainted by what is best for the provider or system, not the patient. Arguments that ALS personnel are too valuable to waste their time and skills treating patients who are not sick enough, or that medical directors cannot train their ALS personnel to perform well enough unless they only see patients who require ALS skills, are arguments that are not centered on the interest of patients.

One researcher found evidence to support the improved effectiveness of ALS over BLS for patients with “certain pathologies.”5 The problem facing EMS systems is how to identify which patients have those pathologies or which are likely to develop those pathologies during the time they are in the prehospital system.

Research into the ability of dispatchers and field personnel to determine who needs ALS can be divided into two categories. There are a number of studies in which patients were categorized either by telephone or on the scene and then evaluated in the ED. In these studies, physicians compared the findings of dispatchers or field crews with what was found in the ED. The authors of these studies found that dispatchers, EMTs and medics could not reliably triage patients. Following are the results of some of those studies:

  • Cone found that “firefighter EMT-Bs working on ambulances without medical criteria or protocols could not reliably determine which patients needed ALS.” In this study, in 87% of the cases where BLS crews cancelled ALS units, the patient required ALS immediately upon arrival at the ED.6
  • Hauswald found that medics could not safely determine which patients did not need an ambulance or ED care.7
  • Another study found that dispatchers could not reliably determine the severity of patient conditions (paramedics at the scene checked the accuracy of dispatcher categorizations).

Other studies have shown that it is relatively “safe” to send BLS units on certain calls. However, in these studies, patient conditions were not checked in emergency departments.8-10 Instead, BLS was considered inappropriate only if the BLS crew called for an ALS ambulance to assist and ALS care was initiated. Hospital records were not checked to determine if “BLS” patients received ALS care upon arrival or if ALS care in the field would have been beneficial. One author concluded there were operational and cost benefits to the department for sending BLS units to these patients.9 However, better care for patients receiving the BLS ambulance was not listed as a benefit.

Full Service

The CEMR team concluded that any system designed from the patient’s viewpoint must ensure that patients got appropriate care no matter how they entered the system, whether by dialing 9-1-1 or calling a seven-digit number for nonemergency ambulance service.3 Two studies support the idea that neither the general public nor medical professionals are good at determining whether patients need an ambulance, much less whether it should be ALS or BLS.

A 1987 study examined inappropriate ambulance use and unmet need in an emergency department.11 Physicians reviewed ED patient records after the fact to determine whether or not patients should have come to the ED by ambulance. The records were then examined to see who had actually arrived by ambulance and who had not. Those who used the ambulance but were determined not to need it were identified as “inappropriate use,” those who should have used the ambulance but did not were identified as having “unmet need.” The rates were 42% and 58%, respectively.

A study conducted in a full-service, all-ALS system in a Kansas City PUM in 1992 examined calls received on their seven-digit nonemergency number and categorized as only requiring BLS by paramedic dispatchers at the time of dispatch.12 Because the system was all ALS, paramedic units responded to all calls. The authors found that in 11.7% of calls dispatchers thought only needed BLS, ALS services were provided; 3% of the calls required an invasive ALS procedure, including intubation. This figure is particularly striking when remembering that only 20%– 30% of 9-1-1 calls require ALS services.

Thus, the team reasoned that in order to provide maximum benefit and safety to patients, all requests for ambulance service, both emergency and nonemergency, should be received by the same center, triaged and serviced by an ALS unit.

No Screening

The team also included provisions in the system design to guarantee that any patient requesting service would receive it, regardless of ability to pay or presumed medical condition. Several systems had implemented dispatch systems in which nurses screened out calls that were determined not to be emergencies. These programs were implemented to reduce expenses. In one system, nurses eliminated enough call volume to reduce the number of ambulances; however, in that system, when a nurse refused to send an ambulance to an unconscious patient, the patient died, and questions arose about the safety of “call screening.”13

Since the original research, other studies have confirmed the dangers of allowing dispatchers and field crews to refuse service to persons requesting aid. One set of studies on the subject tried to document the outcomes of patients who refuse service and/or are refused service by medics. As field providers realize, the line between a “patient refusal” and a “provider-initiated refusal” is often blurred.

Studies demonstrating the danger of refusals in general include a study that found 11% of minors whose parents refused treatment were admitted to the hospital; 84% of them received some sort of medical follow-up either in the ED or a physician’s office.14

One study found that 70% of elderly patients refusing care obtained follow-up, and of those, there was a 32% admission rate.15 This confirmed findings in another study that found patients over 65 had a “propensity to re-contact paramedics after refusing care.”16

Previously, one research group had found a 6% admission rate for patients who refused care. They warned that EMS systems were exposed to an “undefined medico-legal risk.”17

In a study of paramedic-initiated refusals in 1992, in which patients who had been refused care by paramedics were examined, the authors found that 25% of the patients had been subsequently admitted to the hospital and two had died.18

Again, no one argues that denying care or transport is good for the patients. The reasons given for these policies were that they enabled agencies to provide better response times at less cost and with more experienced medics. By placing patient care as its first priority, the CEMR team was constrained to design its system to deliver paramedic care and transport to all patients, cost-effectively, without jeopardizing care to any particular subgroup. There are systems that still allow medics to refuse care to patients if they determine the patient does not require emergency service.19 PUMs, on the other hand, do not.

Financial Considerations

As a matter of policy, the team designed the model to maximize third-party billings in order to achieve financial stability and create value. The logic was straightforward: Many people have insurance. When ambulance providers do not bill, it is the insurance companies and third parties (Medicare and Medicaid) that benefit, not the insured patient. Once people have paid their premiums or taxes, it is the third-party payor who receives a subsidy when they are not billed for services provided and covered.20

Response Time

At the time, as now, there was evidence that rapid response to life-threatening emergencies was linked with survival. The team identified cardiac arrest as the most serious emergency to which the system would respond, and, based on research being conducted in Seattle, established response time standards.21 The eight-minute standard was an attempt to establish a response time standard for ALS units that met several priorities: patient care, cost-effectiveness and value. Clearly, a one-minute response would be clinically more effective than eight, but the team was attempting to design a cost-effective system, as well as one that would provide good clinical care.

PUM Structure

Once the team identified the economic characteristics of the ambulance industry and the clinical characteristics that were required for ideal patient care, it set about creating a system structure that would produce the desired performance with medical and financial accountability. The emphasis on performance accountability differentiated PUMs from other system designs. If an organization failed to meet the clinical response time or customer satisfaction standards in a PUM, it would be replaced. In many other system designs, failure results in a budget increase.3

The PUM was also designed to ensure accountability by making it possible to replace a contractor immediately for failure to perform. This is known as a “guarantee of uninterrupted service.”22 Accountability and guarantee of uninterrupted service are accomplished using the entities described below. Each entity has specific and unique responsibilities that create a set of “checks and balances” in which the contractor and the authority are accountable for the quality and cost of care provided.23

Local jurisdiction

Single or multiple jurisdictions create a PUM system by adopting enabling ordinances that:

  • Create a public nonprofit authority to operate the EMS system and appoint a board of directors.
  • Establish response time standards and recognize the authority of the system’s medical control board.
  • Establish rate schedules and levels of subsidy.

The role of local government is to create the legal structure of the system and set the clinical and economic parameters under which it will operate.


The ambulance authority is charged with four main duties:

  • Purchasing and managing the EMS system’s infrastructure, including buildings, vehicles and equipment.
  • Overseeing system finances: operating the billing system, collecting user fees, as well as operating the subscription program.
  • Conducting a competitive bid process to select an ambulance contractor to operate the system in accordance with its standards.
  • Overseeing contractor operations, including response time performance, to ensure that the contractor complies with all requirements of the ambulance contract.

Medical Direction

The medical control board, or emergency physician advisory board, is composed of representatives from each ED in the system. In some instances, board representatives are elected from a larger body representing all the emergency departments in other systems. These physicians are responsible for:

  • Providing off-line medical control, including adoption of protocols and guidelines.
  • Investigating complaints and conducting clinical care audits.
  • Overseeing on-line medical control.
  • Hiring and overseeing the medical director.


The contractor, who is selected through a competitive bid process, is responsible for the following major duties:

  • Hiring and supervising staff required to operate the EMS system in accordance with local ordinance and the competitively awarded contract, including dispatchers, paramedic crews, mechanics and vehicle service technicians, supervisors, managers and necessary support staff.
  • Providing ALS service to each request for ambulance service in conformance with the response time standards of the system.
  • Providing adequate billing information to the authority.
  • Cooperating fully with the medical director and medical control board in their oversight of clinical care in the system.

Each entity has unique responsibilities. The system of checks and balances ensures accountability for results, both clinical and financial.

FD First Response

The PUM model was designed to include fire department first response to life-threatening emergencies. Based on original and subsequent studies, the team concluded that the initiation of BLS, and now AED, is critical to survival in cardiac arrest.5 They also realized that fire first response was cost- effective, particularly when underutilized fire suppression resources could be used for these critical lifesaving responses.

The PUMs will periodically compile their performance measures, as listed above, to compare levels of quality and cost.24


The PUM model is unique because its features were chosen based on research about the clinical, economic and political characteristics of EMS in an effort to design a system that placed patient care as its highest priority. The system is also efficient and cost-effective by design. Communities disciplined enough to follow the public utility model have achieved the results the model was designed to deliver: clinical excellence, response time reliability, cost-effectiveness and value.


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  2. Stout J. Interview, 2004, Richmond, VA.
  3. Stout J. System Design in Prehospital Systems Medical Oversight, pp. 81–97. A. Kuehl, editor. St. Louis, MO: Mosby-Year Book Inc., 1994.
  4. Frank R. Microeconomics and Behavior, 4th ed. Boston, MA: Irwin McGraw Hill, 2000.
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  7. Hauswald M. Can paramedics safely decide which patients do not need ambulance transport or emergency department care? Prehosp Emerg Care 6(4):383–386, 2002.
  8. Bailey ED, O’Conner R, Ross R. The use of emergency medical dispatch protocols to reduce the number of inappropriate scene responses made by advanced life support personnel. Prehosp Emerg Care 4(2):186–189, 2000.
  9. Curka PA, et al. Emergency medical services priority dispatch. Ann Emerg Med 22(11):1688–1695, 1993.
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  11. Rademaker A, Powell D, Read J. Inappropriate use and unmet need in paramedic and nonparamedic ambulance systems. Ann Emerg Med 16(5):553–556, 1987.
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  13. Clawson J. Priority dispatching after Dallas: Another viewpoint. JEMS 10(5):36–37, 1984.
  14. Seltzer A, et al. Outcome study of minors after parental refusal of transport. Prehosp Emerg Care 5(3):278–283, 2001.
  15. Vilke G, et al. Follow-up of elderly patients who refuse transport after accessing 9-1-1. Prehosp Emerg Care 6(4):391–395, 2002.
  16. Moss S, et al. Outcome study of prehospital patients signed out against medical advice by field paramedics. Ann Emerg Med 31(2):247–250, 1998.
  17. Sucov A, et al. The outcome of patients refusing prehospital transportation. Prehosp Disast Med 7(4):365–371, 1992.
  18. Zachariah B, et al. Follow-up and outcome of patients who decline or are denied transport by EMS. Prehosp Disast Med 7(4):359–371, 1992.
  19. Persse D, Key C, Baldwin B. The effect of a quality improvement feedback loop on paramedic-initiated nontransport of elderly patients. Prehosp Emerg Care 6(1):31–35, 2002.
  20. Stout J. Public utility models part three: The major constraints. JEMS 6(7):35–37, 1980.
  21. Eisenberg M, Bergner L, Hallstrom A. Cardiac resuscitation in the community. JAMA 241(18):1905–1907, 1979.
  22. Stout J. Public utility model revisited part two: Ten essential features. JEMS 11(3):71–74, 1985.
  23. Stout J. Public utility models part two: The principal elements. JEMS 6(6):35–40, 1980.
  24. Overton J. High Performance and EMS: Market Study 2002. North American Association of Public Utility Models 2002: Richmond, VA.
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