In 2000, about 3,900 nonfederal, general medical hospitals nationwide reported providing emergency care in emergency departments. Of these, just over half were located in MSAs. From 1997 through 2000, while the number of emergency department visits increased about 14 percent, the number of hospitals with emergency departments decreased by about 2 percent. The result was that the average number of visits per emergency department increased by 16 percent. Many hospitals expanded the physical space and number of treatment spaces in their emergency departments during that time. Recent reports have raised concern that many of the nation’s emergency departments are experiencing high demand and crowded conditions. An April 2002 report for the American Hospital Association, while limited in scope and the proportion of hospitals responding, found that officials at many hospitals in urban areas described their emergency departments as operating at or above capacity. While there are no comprehensive studies on the consequences of crowded conditions, health care researchers and clinicians report that crowding has multiple effects, including prolonged pain and suffering for some patients, long patient waits, increased transport times for ambulance patients, inconvenience and dissatisfaction for the patients and their families, and increased frustration among medical staff. In addition to delays in treatment, some emergency department directors have reported that patient care was compromised and patients experienced poor outcomes as a result of crowded conditions in emergency departments. Because the medical conditions of patients who come to the emergency department can range from mild injuries such as ankle sprains to serious traumas such as from automobile accidents—and can also include patients with chronic conditions such as asthma or diabetes—the space, equipment, and medical personnel resources required to treat patients vary. As a result, there are no specific criteria, such as a ratio of patients to staff, to define when an emergency department is too crowded and its providers are overloaded. Rather, emergency department administrators and physicians say “they know it when they see it.” In the absence of specific criteria to define when an emergency department is crowded, health care researchers suggest using several available indicators to point to crowded conditions. Based on our review of studies and discussions with experts, we chose three indicators of emergency department crowding. As shown in table 1, all three are useful indicators but all three also have limitations. One indicator of a crowded emergency department is the number of hours a hospital is on diversionary status. Under federal law, all hospitals that participate in Medicare are required to screen—and if an emergency medical condition is present, stabilize—any patient who comes to the emergency department, regardless of the individual’s ability to pay. Under certain circumstances where a hospital lacks staffing or facilities to accept additional emergency patients, the hospital may place itself on “diversionary status” and direct en route ambulances to divert to another hospital. In general, hospitals ask EMS providers to divert ambulances to other medical facilities because their emergency department staff are occupied and unable to promptly care for new arrivals or specific services within the hospitals, such as the intensive care units, are filled and unable to accommodate the specialized needs of new ambulance arrivals. While on diversion, hospitals must still treat any patients who arrive by ambulance, and in some cases, local community protocols allow ambulances to go to a hospital that is on diversion when the patient asks to go to that hospital or if the patient needs immediate medical treatment. In addition, even while on diversion, the emergency department is still required to screen and treat nonambulance patients—those patients who walk in or otherwise arrive at the hospital—and these patients make up the vast majority of visits to the emergency department. The Department of Health and Human Service’s (HHS) National Center for Health Statistics estimates that in 2000 about 14 percent of emergency department visits were made by patients who arrived by ambulance, while 78 percent of visits were made by patients who arrived at the emergency department by “walking in.” For the remaining visits, the patients were brought in by the police or social services (1.5 percent), or the mode of arrival was unknown (6.3 percent). As a measure of crowding, diversion has limitations in that some hospitals, even when crowded, do not have the option to divert ambulances due to state or local regulations, because there are no other medical facilities nearby, or because of individual hospital policies. Hospital practices may vary regarding the threshold at which a hospital goes on diversion. Local community or hospital policies may also differ regarding the length of time a hospital may remain on diversion. (See app. II for the local community policies for the six sites we visited). However, for those hospitals that can go on diversion, it is an indicator of how often these emergency departments believe they can no longer handle additional ambulance patients. A second indicator suggested by health care researchers is the number of patients who are “boarding” in the emergency department. These patients remain in the emergency department after the decision has been made to admit them to the hospital or transfer them to another facility. Many factors can contribute to the length of time a patient is boarded in the emergency department, such as inpatient bed availability, staffing levels, and the complexity of a patient’s condition. Regardless of the reason, while waiting for an inpatient bed or transfer, these patients still require care and take up treatment space, equipment, and staff time in the emergency department, shrinking the department’s resources available to treat other emergency patients. A limitation of using boarding as an indicator is that many hospitals do not collect this information regularly and can only estimate how often and how long patients board in their emergency departments. In addition, it is possible that emergency departments board patients while also having available treatment spaces to see additional patients. Finally, the proportion of patients who leave after triage but before receiving a medical evaluation is another indicator suggested by health care researchers that could indicate a crowded emergency department. Long waits in the emergency department can delay needed care and contribute to an increase in the number of people who choose to leave the emergency department before receiving a medical evaluation. A limitation to this indicator is that, because emergency department staff triage patients, those with nonemergent conditions generally wait the longest and may be most likely to tire of waiting and leave before a medical evaluation. However, relatively mild conditions could potentially become more serious if patients do not receive needed medical care because they leave the emergency department before being evaluated and treated. A study of the consequences of leaving the emergency department prior to a medical evaluation at one public hospital found that 46 percent of those who left were judged to need immediate medical attention, and 11 percent who left were hospitalized within the next week. Although most emergency departments across the country reported some degree of crowding on one or more of the three indicators, the problem is much more pronounced in some hospitals than in others. In addition, hospitals in the largest metropolitan areas (those with populations of 2.5 million or more), communities with high population growth, and communities with above average percentages of people without health insurance had higher levels of crowding. Analysis of responses to our nationwide survey showed substantial variation in the degree of crowding reported across all three indicators— diversion, boarding, and patients leaving before a medical evaluation. Hospitals ranged from little or no crowding to crowding that persisted for a substantial part of the time. Diversion. In total, we estimate that about 2 of every 3 of the hospitals in our survey universe went on diversion at least once during fiscal year 2001. We estimate that about 2 in every 10 of these hospitals were on diversion for more than 10 percent of the time, and about 1 in every 10 was on diversion for more than 20 percent of the time—or about 5 hours per day. Figure 1 shows the variation in the amount of diversion reported by hospitals in MSAs. Diversion varies greatly by MSA. Figure 2 shows each MSA and the share of hospitals within the MSA that reported being on diversion more than 10 percent of the time—or about 2.4 hours or more per day—in fiscal year 2001. Of the 248 MSAs for which data were available, 171 (69 percent) had no hospitals reporting being on diversion more than 10 percent of the time. By contrast, 53 MSAs (21 percent) had at least one-quarter of responding hospitals on diversion for more than 10 percent of the time. Boarding. Boarding patients for 2 hours or more in the emergency department while waiting for an inpatient bed or transfer occurred to some extent at an estimated 9 of every 10 hospitals. As part of our survey, we examined what percentage of emergency patients who boarded spent 2 hours or more in boarding status and the average number of hours patients boarded. As figure 3 shows, while many hospitals reported boarding less than 25 percent of boarded patients for 2 hours or more in the past 12 months, about one-third of them reported boarding 75 percent or more of their boarded patients for that long. About 1 in every 5 hospitals reported an average boarding time in their emergency departments of 8 hours or more. Boarding varies greatly by MSA. Figure 4 shows each MSA and the extent to which responding hospitals within the MSA reported that of those patients who boarded in the past 12 months, at least half spent 2 hours or more in boarding status, and the average boarding time was 8 hours or more. Of the 206 MSAs for which data were available on the percentage of patients boarded and the average number of hours boarded, 112 MSAs (54 percent) had no hospitals reporting that they met these criteria. In contrast, 52 of the 206 MSAs (25 percent) had at least one-fourth of responding hospitals reporting that they boarded at least half of their patients for 2 hours or more and had an average boarding time of at least 8 hours. Patients Leaving before a Medical Evaluation. From our nationwide survey of hospitals, we estimate that the median percentage of patients who left after triage but before a medical evaluation in fiscal year 2001 was 1.4 percent.