Thousands of emergency departments operate in the United States, seeing millions of patients each year. In our 2003 report on emergency department crowding, we reported on the extent of crowding in metropolitan areas. Researchers have used three indicators--diversion, wait times, and boarding--in examining emergency department crowding. Between 2001 and 2006, according to NCHS estimates, the number of emergency departments operating in the United States ranged from about 4,600 to about 4,900. During the same period, the estimated number of visits to U.S. emergency departments exceeded 107 million visits each year, ranging from about 107 million visits in 2001 to about 119 million visits in 2006. (See table 1.) Most hospitals with emergency departments are located in metropolitan areas, and the majority of emergency department visits occurred in metropolitan areas of the United States. In 2006, about two-thirds of hospitals with emergency departments were located in metropolitan areas compared to about one-third in nonmetropolitan areas. In the same year, about 101 million (85 percent) of the approximately 119 million emergency department visits occurred in metropolitan areas compared to about 18 million (15 percent) visits in nonmetropolitan areas. (See fig. 1.) Patients come to the emergency department with illnesses or injuries of varying severity, referred to as acuity level. Each acuity level corresponds to a recommended time frame for being seen by a physician--for example, patients with immediate conditions should be seen within 1 minute and patients with emergent conditions should be seen within 1 to 14 minutes. In 2006, urgent patients--patients who are recommended to be seen by a physician within 15 to 60 minutes--accounted for the highest percentage of visits to the emergency department. (See fig. 2.) The expected sources of payment reported for patients receiving emergency department services also vary. For example, from 2001 through 2006 patients with private insurance accounted for the highest number and percentage of visits to the emergency department. During the same period, the percentage of uninsured patients seeking care in emergency departments ranged between 15 and 17 percent of total visits, and the percentage of patients visiting emergency departments with Medicare ranged between 14 and 16 percent. See appendix II for additional data on expected sources of payment and emergency department utilization. In 2003, using three indicators that point to situations in which crowding is likely occurring--diversion, patients leaving before a medical evaluation, and boarding--we reported that emergency department crowding varied nationwide. We also reported that crowding was more pronounced in certain types of communities, and that crowding occurred more frequently in hospitals located in metropolitan areas with larger populations, higher population growth, and higher levels of uninsurance. We reported that crowding was more evident in certain types of hospitals, such as in hospitals with higher numbers of staffed beds, teaching hospitals, public hospitals, and hospitals designated as certified trauma centers. In terms of factors that contribute to crowding, we reported that crowding is a complex issue and no single factor tends to explain why crowding occurs. However, we found that one key factor contributing to crowding was the availability of inpatient beds for patients admitted to the hospital from the emergency department. Reasons given by hospital officials and researchers we interviewed for not always having enough inpatient beds to meet demand from emergency patients included economic factors that influence hospitals' capability to meet periodic spikes in demand and emergency department admissions competing with other admissions for inpatient beds. Other additional factors cited by researchers and hospital officials as contributing to crowding included the lack of availability of physicians and other community services--such as psychiatric services-- and the fact that emergency patients are older, have more complex conditions, and have more treatment and tests provided in the emergency department than in prior years. Further, we reported that hospitals and communities had conducted a wide range of activities to manage crowding in emergency departments, but that problems with crowding persisted in spite of these efforts. These activities included efforts to expand capacity and increase efficiency in hospitals, and community activities to implement systems and rules to manage diversion. These efforts were unable to reverse crowding trends at hospital emergency departments, and we found that studies assessing the effect of these efforts were limited. Researchers use the indicators we reported on in 2003 to point to situations in which crowding is likely occurring in emergency departments. These indicators can point to when crowding is likely occurring but they also have limitations. For example, patients boarding in the emergency department can indicate that the department's capacity to treat additional patients is diminished, but it is possible for several patients to be boarding while the emergency department has available treatment spaces to see additional patients. Table 2 provides the definition of the three indicators of emergency department crowding we reviewed in this report--diversion, wait times, and boarding--and lists the usefulness and limitations of using these indicators to gauge crowding. Regarding wait times, in our 2003 report, we used "left before a medical evaluation" as an indicator of crowding related to long wait times in an emergency department. Since we issued our report in 2003, researchers have used intervals of wait times--including the length of time to see a physician and the total length of time a patient is in the emergency department--to indicate when an emergency department is crowded. As a result, for this report, we examined wait times more broadly, including data on the time for patients to see a physician, length of stay in the emergency department, and visits in which the patient left before a medical evaluation. Researchers have developed a conceptual model to analyze the factors that contribute to emergency department crowding and develop potential solutions. This model partitions emergency department crowding into three interdependent components: input, throughput, and output. Although factors in many different parts of the health care system may contribute to emergency department crowding, the model focuses on crowding from the perspective of the emergency department. (See fig. 3.) Researchers have used the input-throughput-output model to explain the connection between factors that contribute to emergency department crowding and indicators of crowding. The three indicators of emergency department crowding--diversion, wait times, and boarding--are most directly related to the input, throughput, and output components, respectively, of the model; but the causes of these indicators can relate to other components. For example, a hospital emergency department might experience long wait times--an indicator associated with the throughput component--because of delays in patients receiving laboratory results (related to throughput) or because staff are busy caring for patients boarding in the emergency department due to a lack of access to inpatient beds (related to output). Similarly, an emergency department may divert ambulances (related to input) because the emergency department is full due to the inability of hospital staff to move admitted patients to hospital inpatient beds (related to output). We found that ambulance diversions continue, wait times have increased, and reports of boarding in hospital emergency departments persist. Articles we reviewed also reported on the effect of crowding on quality of care and on strategies proposed to address crowding. National data show that the diversion of ambulances continues to occur, but that the percentage of hospitals that go on diversion and the average number of hours hospitals spend on diversion varied by year. According to NCHS estimates, in 2003, 45 percent of U.S. hospitals reported going on diversion, and in 2004 through 2006, between 25 and 27 percent reported doing so. Of hospitals that reported going on diversion, the average number of hours they reported spending on diversion varied with an average of 276 hours in 2003 and an average of 473 hours in 2006. (See table 3.) NCHS officials provided the percentage of missing diversion data for each year, which ranged from 3.75 percent in 2003 to 29.1 percent in 2005. NCHS officials, however, were unable to provide an explanation for the variation of the percentage of hospitals going on diversion in the United States and average hours U.S. hospitals reported spending on diversion for these years. NCHS reported that hospitals in metropolitan areas spent more time on diversion than hospitals in nonmetroplitan areas in 2003 through 2004: almost half of hospitals in metropolitan areas NCHS surveyed reported spending more than 1 percent of their total operating time on diversion in 2003 through 2004, compared to 1 in 10 hospitals in nonmetropolitan areas. Some hospitals, however, reported that their state or local laws prohibit diversion. Other articles that reported on results from surveys also indicated that diversion has continued to occur in some hospitals. In 2006 and 2007, the American Hospital Association conducted surveys of community hospital chief executive officers that asked how much time hospitals spent on diversion in the previous year. The results from these surveys show that some hospitals reported going on diversion. In both American Hospital Association surveys, urban hospitals more often reported diversion hours than rural hospitals. For example, among hospitals responding to the 2006 American Hospital Association survey, about 64 percent of respondents from urban hospitals reported going on diversion, compared to about 17 percent of respondents from rural hospitals. In addition, articles reporting on emergency department crowding in California and Maryland also found that diversion continues to occur and that the time hospitals spent on diversion varied. National data from NCHS indicate that wait times in the emergency department have increased and in some cases exceeded recommended time frames. For example, the average wait time to see a physician increased from 46 minutes in 2003 to 56 minutes in 2006. Average wait times also increased for patients in some acuity levels. (See fig. 4.) For emergent patients, the average wait time to see a physician increased from 23 minutes to 37 minutes, more than twice as long as recommended for their level of acuity. For immediate, emergent, urgent, and semiurgent patients, NCHS estimates show that some patients were not seen within the recommended time frames for their acuity level. The average wait time to see a physician increased in emergency departments in metropolitan areas, and wait times were longer in emergency departments in metropolitan areas than in nonmetropolitan areas in 2006. In metropolitan-area emergency departments, the average wait time to see a physician increased from 51 minutes in 2003 to 60 minutes in 2006. In nonmetropolitan-area emergency departments, the average wait time to see a physician was estimated to be about 26 minutes in 2003 and 33 minutes in 2006. According to NCHS data, the average length of stay in the emergency department and the percentage of visits in which patients left before a medical evaluation also increased. (See table 4.) See appendix IV for additional information about wait times in the emergency department. More than 25 percent of the 197 articles we reviewed discuss the practice of boarding patients in emergency departments, and officials we interviewed noted that the practice of boarding continues. For example, in 2006 IOM reported that boarding continues to occur and has become a typical practice in hospitals nationwide, with the most boarding occurring at large urban hospitals. One article published in a peer-reviewed journal reported that it is not unusual for critically ill patients to board in the emergency department. In addition, officials we interviewed noted that the practice of boarding patients in emergency departments persists. In particular, officials from the Center for Studying Health System Change noted that boarding still occurs in emergency departments and continues to be one of the main indicators of emergency department crowding. Officials from ACEP noted that boarding continues to occur in emergency departments nationwide and remains a concern for emergency physicians and their patients. National data on the boarding of patients in the emergency department, however, have been limited. In 2006, IOM reported that hospital data systems do not adequately monitor or measure patient flow, and therefore may be limited in their ability to capture data on boarding. For example, few systems distinguish between when a patient is ready to move to another location for care and when that move actually takes place. In addition, from 2001 to 2006, NCHS did not collect data on boarding because, according to NCHS officials, data on boarding were not easily obtained from patient records. A question about emergency department boarding was added to NCHS's NHAMCS questionnaire in 2007; however, data from this survey were not available at the time we conducted our analysis. Other articles that reported on results of surveys conducted by professional associations supported officials' statements that boarding has been widespread. For example, in an article reporting on a 2005 ACEP survey of emergency department directors with a 30 percent response rate, 996 of the 1,328 respondents reported that they boarded patients for at least 4 hours on a daily basis and more than 200 respondents reported that they did so for more than 10 patients per day on average. Ten of the articles we reviewed and officials from ACEP and the Society for Academic Emergency Medicine whom we interviewed raised concerns about the adverse effect of diversion, wait times, or boarding on the quality of patient care, but quantitative evidence of this effect has been limited. Officials from ACEP reported that research has begun to analyze the effect of crowding on patient quality of care, and that anecdotal reports indicate patients are being harmed. Ten of the articles we reviewed discussed the effect of diversion, wait times, or boarding on quality of care. One of these articles, the 2006 IOM report, noted that ambulance diversion could lead to catastrophic delays in treatment for seriously ill or injured patients and that boarding may enhance the potential for errors, delays in treatment, and diminished quality of care. Other articles--some of which were published in peer-reviewed journals--also discussed the effect of crowding on the quality of patient care, including the following: An examination of the relationship between trauma death rates and hospital diversion, which suggested that death rates for trauma patients at two hospitals may be correlated with diversion at these hospitals. A review of 24 hospital emergency departments that suggested when an emergency department experienced an increase in the number of patients leaving before a medical evaluation, fewer patients with pneumonia at the emergency department received antibiotics within the recommended 4 hours. Information from a database of 90 hospitals that showed patients who were boarded in the emergency department for more than 6 hours before being transferred to the hospital's intensive care unit had an almost 5 percent higher in-hospital mortality rate than those who were boarded for less than 6 hours. Five other articles reported potential associations between diversion, boarding, and wait times and decreased quality of patient care, including articles on the effect of increasing wait times for nonurgent patients in the emergency department and delayed treatment time for those patients who left before a medical evaluation. While these studies support the widely held assertion that emergency department crowding adversely affects the quality of patient care, a 2006 National Health Policy Forum report stated that the consequences of crowded emergency departments on quality of care have not been studied comprehensively and therefore little quantitative evidence is available to confirm this assumption. Officials from the Society for Academic Emergency Medicine reported that diversion, wait times, and boarding can contribute to reduced quality of care and worse patient outcomes. In addition, officials from both ACEP and the Society for Academic Emergency Medicine noted that additional studies about the effects of diversion, wait times, and boarding on quality of care are needed. Articles we reviewed, and officials and an expert we interviewed, discussed a number of strategies that have been proposed, and in some cases tested, that could decrease emergency department crowding. These strategies relate to the three interdependent components--input, throughput, and output--of the model of emergency department crowding developed by researchers. While several of these strategies have been tested, the assessment of their effects has generally been limited to one or a few hospitals and we found no research assessing these strategies on a state or national level. Table 5 outlines some strategies to address emergency department crowding and, to the extent they have been tested, the assessment of their effects on the indicators of crowding. Available information suggests that a lack of access to inpatient beds is the main factor contributing to emergency department crowding. Additionally, other factors--a lack of access to primary care, a shortage of available on- call specialists, and difficulties transferring, admitting, or discharging psychiatric patients--have also been reported as contributing to crowding. Of the 77 articles we reviewed that discussed factors contributing to crowding, 45 articles reported a lack of access to inpatient beds as a factor contributing to emergency department crowding, with 13 of these articles reporting it was the main factor contributing to crowding. (See table 6.) In addition, two individual subject-matter experts we interviewed also reported a lack of access to inpatient beds as the main factor that contributes to emergency department crowding. When inpatient beds are not available for ill and injured patients who require hospital admission, the emergency department may board them, and these patients take up extra treatment spaces and emergency department resources, leaving fewer resources available for other patients. One of the reasons that emergency departments are unable to move admitted patients to inpatient beds may be due to competition between emergency department admissions and scheduled hospital admissions-- for example, for elective surgical procedures--which we also reported on in 2003. This reason was reported by 9 articles we reviewed and by officials from ACEP, the Society for Academic Emergency Medicine, the Center for Studying Health System Change, and three individual subject- matter experts whom we interviewed. In 2006, IOM reported that hospitals might prefer scheduled admissions over admissions from the emergency department because emergency department admissions are considered to be less profitable. One reason that admissions from the emergency department are considered to be less profitable is because these admissions tend to be for medical conditions, such as heart failure and pneumonia, rather than surgical procedures, such as joint replacement surgeries and scheduled cardiovascular procedures. Available data from AHRQ's 2006 Healthcare Cost and Utilization Project show all 20 of the most-prevalent diagnosis-related groups (DRG) associated with admissions from the emergency department in 2006 were for medical conditions rather than surgical procedures. In contrast, 7 of the 20 most- prevalent DRGs for nonemergency department admissions in 2006 were for surgical conditions. Officials from the Society for Academic Emergency Medicine told us that because treating surgical conditions is considered more profitable for a hospital than treating emergency medical conditions, hospitals had an incentive to reserve beds for scheduled surgical admissions rather than to give them to patients admitted from the emergency department. Available information suggests that other factors also contribute to emergency department crowding including a lack of access to primary care, a shortage of available on-call specialists, and difficulties transferring, admitting, or discharging psychiatric patients. Twenty-two articles we reviewed reported a lack of access to primary care as a factor contributing to emergency department crowding. For example, one of these articles reported that difficulty in receiving care from a primary care provider was associated with an increase in nonurgent emergency department use. Another article described a study in New Jersey that indicated that almost one-half of all emergency department visits within the state that did not result in hospital admission could have been avoided with improved access to primary care services. Additionally, officials from the Center for Studying Health System Change and the Society for Academic Emergency Medicine mentioned a lack of access to primary care as a factor contributing to emergency department crowding. When patients do not have a primary care physician, or cannot obtain an appointment with a primary care physician, they may go to the emergency department to seek primary care services. In addition, patients who do not have access to primary care may defer care until their condition has worsened, potentially increasing the emergency department resources needed to treat the patient's condition. These situations involve patients that could have been treated outside of the emergency department and may add to the number of patients seeking care at the emergency department. Articles we reviewed provided conflicting information on the effect of increasing numbers of uninsured patients on emergency department crowding. Five of the 22 articles that mentioned a lack of access to primary care as a factor also reported that increasing numbers of uninsured patients also contributed to emergency department crowding. For example, 1 article indicated that a reason for longer wait times at 30 California hospitals in lower-income areas was that these hospitals treat a disproportionate number of uninsured patients who may lack access to primary care. Two other articles we reviewed, however, suggested that increasing numbers of uninsured patients is not a factor contributing to crowding. For example, the Center for Studying Health System Change reported that contrary to the popular belief that uninsured people are the major cause of increased emergency department use, insured Americans accounted for most of the 16 percent increase in visits between 1996 through 1997 and 2000 through 2001. In addition, officials from AHRQ noted that a larger proportion of patients using the emergency department are insured than uninsured. Seven articles and officials from the Center for Studying Health System Change, ACEP, the American Hospital Association, and the American Medical Association whom we interviewed reported that a shortage of on- call specialists available to emergency departments is a factor that contributes to emergency department crowding. Hospitals often employ on-call specialists, meaning specialists such as neurosurgeons or orthopedic surgeons who only travel to the hospital or emergency department when needed and called. When patients wait for long periods in the emergency department for an on-call specialist who is not immediately available--for example, busy covering other hospitals or in surgery--these patients might not receive timely and appropriate care. In addition, these patients may utilize treatment spaces and resources that could be used to treat other patients, potentially crowding the emergency department. In 2006 IOM reported that over the preceding several years, hospitals had found it increasingly difficult to secure specialists for their emergency department patients. Additionally, another article reported the results of a 2007 American Hospital Association survey of hospital chief executive officers that asked about maintaining on-call specialist coverage for the emergency department. While this survey had a low response rate, it indicates that hundreds of emergency departments reported experiencing difficulty in maintaining on-call coverage for certain specialists. For example, of those chief executive officers that responded to the survey (840 chief executive officers; 17 percent of those surveyed), 44 and 43 percent noted difficulty in maintaining emergency department on-call coverage for orthopedic surgeons and neurosurgeons, respectively. Additionally, officials from the Center for Studying Health System Change told us that delays in obtaining specialty services may contribute to crowding. None of the articles we reviewed, nor officials or individual subject-matter experts we interviewed, quantitatively assessed the relationship between the availability of on-call specialists and emergency department crowding. Three articles we reviewed and officials from NCHS, ACEP, and the Center for Studying Health System Change whom we interviewed reported difficulties transferring, admitting, or discharging psychiatric patients from the emergency department as a factor contributing to emergency department crowding. One of these articles reported the results of a national ACEP survey of emergency physicians that asked about psychiatric patients in the emergency department. Of the physicians responding to the survey (328 physicians; approximately 23 percent of those surveyed), about 40 percent reported that, on average, psychiatric patients waited in the emergency department for an inpatient bed longer than 8 hours after the decision to admit them had been made, including about 9 percent who reported that psychiatric patients waited more than 24 hours. Medical patients in the emergency department--those diagnosed with nonpsychiatric conditions--generally waited less time for an inpatient bed: 7 percent of responding physicians reported that, on average, medical patients waited longer than 8 hours after the decision to admit them had been made; slightly less than 1 percent reported that the medical patients waited more than 24 hours. In addition, the survey respondents indicated psychiatric patients waiting to be transferred or discharged added to the burden of an already crowded emergency department and affected access for all patients requiring care. Also, officials from NCHS said that psychiatric patients in the emergency department are a national concern because they are frequent visitors to the emergency department and they may spend more than 24 hours in an emergency department. National data from NCHS show that, in 2006, psychiatric patients constituted a small percentage of emergency department visits but had a longer average length of stay in the emergency department. Almost 3 percent of emergency department visits in 2006 were by patients presenting with a complaint of a psychological or mental disorder and these patients had an average length of stay in the emergency department that was longer than the average length of stay for all other visits (397 minutes, compared to 194 minutes for all other visits). Emergency department patients with psychiatric disorders may need to be isolated from other patients and may require resources that are not available in many hospitals. Hospital emergency departments often have limited or no specialized psychiatric facilities and emergency department staff may experience difficulties transferring such patients to other facilities, admitting them to the hospital, or discharging them from the emergency department. Additionally, emergency department staff may spend a disproportionate amount of time and resources caring for psychiatric patients while these patients wait for transfer, admission, or discharge. Our literature review identified five other factors that may contribute to emergency department crowding. For example, in 2006 IOM reported these five factors--an aging population, increasing acuity of patients, staff shortages, hospital processes, and financial factors--as possible factors that might contribute to emergency department crowding, and these five factors were also mentioned in 14 other articles we reviewed. However, during our interviews with officials and individual subject-matter experts, there was little mentioned about these factors and how they contribute to crowding. HHS provided comments on a draft of this report, which are included in appendix V. In its comments, HHS noted that the report demonstrates that emergency department wait times continue to increase and frequently exceed national standards. HHS also commented that strengths of the report include its clarity, focus, and tone. In addition, HHS commented on the scope of the report and limitations of the indicators used in it. HHS suggested that the information provided in the report would be strengthened by inclusion of articles published prior to 2003 and articles reporting on studies conducted outside of the United States. We focused our literature review on articles published since 2003 to review information made available since we issued our 2003 report. And while articles reporting on studies conducted outside of the United States may include valuable information regarding aspects of emergency department crowding as it occurs in other countries, we reviewed articles reporting on studies conducted in the United States because our focus was on the U.S. health care system. HHS also commented that the indicators of crowding that we used had limitations. As we noted both in our 2003 report and in this report, these indicators have limitations but, in the absence of a widely accepted standard measure of crowding, they are used by researchers to point to situations in which crowding is likely occurring. HHS also provided technical comments, which we incorporated as appropriate. As agreed with your office, unless you publicly announce the contents of this report earlier, we plan no further distribution until 30 days from the report date. At that time, we will send copies of this report to the Secretary of Health and Human Services and other interested parties. The report will be available at no charge on GAO's Web site at http://www.gao.gov. If you or your staff have any questions about this report, please contact me at (202) 512-7114 or crossem@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff members who made major contributions to this report are listed in appendix VI. To examine national data made available since 2003 on emergency department diversion and wait times, we obtained and reviewed data collected by the National Center for Health Statistics (NCHS) through its National Hospital Ambulatory Medical Care Survey (NHAMCS). We analyzed available NCHS data for 2001 through 2006 on diversion and wait times to determine what changes, if any, have occurred over time. We analyzed wait time data by patient acuity level and hospital characteristics, such as hospital ownership, metropolitan or nonmetropolitan area location, and geographic region. We analyzed wait times in the emergency department using NCHS's data on recommended time for a patient to see a physician based on patient acuity levels. Further, to determine the average length of stay in the emergency department for patients who presented with a psychological or mental disorder, we analyzed emergency department length of stay by the type of patient complaint at time of the visit. We also analyzed NCHS data on emergency department utilization by payer source, including Medicare, Medicaid, and the State Children's Health Insurance Program, self pay, no charge or charity care; and by hospital characteristics, such as whether the hospital was located in a metropolitan or nonmetroplitan area, to provide context for our work. We also reviewed and analyzed data from the Agency for Healthcare Research and Quality's (AHRQ) Healthcare Cost and Utilization Project to determine the diagnosis-related groups (DRG) most commonly associated with hospital admissions from the emergency department and most commonly associated with non-emergency department admissions--information we determined was related to factors that contribute to crowding. We obtained NCHS and AHRQ data beginning with 2001 because these data became publicly available in 2003 or later, meeting the criterion for inclusion in our analysis. Some data were not available from NCHS for all years between 2001 and 2006 because of revisions made by NCHS to questions on surveys used to collect information and because of low response rates to certain questions on these surveys. At the time we conducted our analysis, the most recent year for which data were available from NCHS and AHRQ was 2006. In this report, we present NCHS estimates; for those cases in which we report an increase or other comparison of these estimates, NCHS tested the differences and found them statistically significant. To assess the reliability of national data from NCHS and AHRQ, we interviewed agency officials and reviewed the methods they used for collecting and reporting these data. We resolved discrepancies we found between the data provided to us and data in published reports by corresponding with officials from NCHS to obtain sufficient explanations for the differences. Based on these steps, we determined that these data were sufficiently reliable for our purposes. To examine information available since 2003 about three indicators of emergency department crowding and the factors that contribute to crowding, we conducted a literature review. In examining information made available since 2003 about indicators and factors of crowding during our literature review, we analyzed articles for what was reported on the effect of crowding on patient quality of care and proposed strategies to address crowding. We conducted a structured search of 16 databases that included peer-reviewed journal articles and other periodicals to capture articles published on or between January 1, 2003, and August 31, 2008. We searched these databases for articles with key words in their title or abstract related to emergency department crowding, or indicators and factors of crowding, such as versions of the word "crowding," "emergency department," "diversion," "wait time," and "boarding." We also included articles published on or between January 1, 2003, and August 31, 2008, that were identified as a result of our interviews with federal officials, professional and research organizations, and subject-matter experts. We also searched related Web sites for additional emergency department crowding publications, including articles reporting on surveys conducted by professional organizations, such as the American Hospital Association. For these articles, we identified the number of respondents and response rates, and for those with lower response rates, we noted them in our report. From all of these sources, we identified over 300 articles, publications and reports (which we call articles) published from January 1, 2003, through August 31, 2008. Within the more than 300 articles, we excluded articles that were published outside of the United States, reported on subjects or data from outside the United States, were only available in an abstract form, had a focus other than day-to-day emergency department operations, or were unrelated to emergency department crowding. We supplemented the articles that were not excluded from our search by reviewing references contained in the bibliography of these articles for additional articles published on or between January 1, 2003, and August 31, 2008, on emergency department crowding that met our inclusion criteria. In total, we included 197 articles in our literature review and analyzed these articles to summarize information on emergency department crowding, including information on diversion, wait times, and boarding, the effect of these indicators of crowding on quality of care, proposed strategies to decrease these indicators, and factors that contributed to emergency department crowding. To review a complete bibliography of these articles, see GAO-09-348SP. Additionally, we interviewed officials from federal agencies and one state agency, officials from professional, research, and other hospital-related organizations, and individual subject-matter experts to obtain and review information on indicators of emergency department crowding and factors that contribute to crowding. During our interviews, we asked about the effect of crowding on patient quality of care and proposed strategies for addressing crowding. We interviewed federal officials from the Department of Health and Human Services' Centers for Medicare & Medicaid Services and the Office of the Assistant Secretary for Preparedness and Response, and officials from NCHS and AHRQ who have conducted research on emergency department utilization and crowding. We also interviewed officials from the Massachusetts Department of Public Health to discuss the state's planned implementation of a new diversion policy in January 2009. We interviewed officials from professional organizations, including the American College of Emergency Physicians (ACEP), the American Hospital Association, the American Medical Association, the Emergency Nurses Association, the National Association of EMS Physicians, and the Society for Academic Emergency Medicine. Some officials from ACEP and the Society for Academic Emergency Medicine have published research in peer-reviewed journals. In addition, we interviewed officials from research organizations, such as the California Healthcare Foundation, the Center for Studying Health System Change, the Heritage Foundation, and the Robert Wood Johnson Foundation's Urgent Matters. We interviewed officials from the Joint Commission (an organization involved in hospital accreditation), the Medicare Payment Advisory Commission (an organization that studies Medicare payment issues and reports to Congress), and the National Quality Forum (an organization that develops quality measures for emergency department care). We also interviewed three individual subject-matter experts who have conducted research on emergency department crowding and strategies to reduce crowding. We conducted this performance audit from May 2008 through April 2009 in accordance with generally accepted government auditing standards. Those standards require that we plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our findings and conclusions based on our audit objectives. We believe that the evidence obtained provides a reasonable basis for our findings and conclusions based on our audit objectives. This appendix provides information on nationally-representative estimates of emergency departments and emergency department visits in the United States by characteristics such as patient acuity level, payer source, hospital ownership type, geographic region, and type of area (metropolitan or nonmetropolitan) from the National Center for Health Statistics' (NCHS) National Hospital Ambulatory Medical Care Survey (NHAMCS). Specifically, for 2001 through 2006 this appendix presents the following information: the percentage of emergency departments by hospital ownership type, by geographic region, and by type of area (metropolitan or nonmetropolitan) (table 7); the number and percentage of emergency department visits by acuity level (figure 5) and payer source (table 8); the number and percentage of emergency department visits by hospital ownership type, geographic region, and type of area (table 9); and the number and percentage of emergency department visits that resulted in hospital admissions (table 10). Researchers continue to use diversion, wait times (including patients who left before a medical evaluation), and boarding as indicators to point to situations in which crowding is likely occurring in emergency departments; however, as we reported in our 2003 report, there is no standard measure of the extent to which emergency departments are experiencing crowding. In the absence of a widely-accepted standard measure of crowding, researchers have proposed and conducted limited testing of potential measures of crowding. During our literature review of articles on emergency department crowding published on or between January 1, 2003, and August 31, 2008, we identified proposed measures of crowding that researchers have tested, either in a single hospital setting or for a limited period of time. Table 11 describes these proposed measures. While researchers have claimed varying levels of success using these measures to gauge crowding, we found no widely accepted measure of emergency department crowding, and that none of these measures of crowding had been widely implemented by researchers and health care practitioners. This appendix provides information on nationally-representative estimates of intervals of emergency department wait times in the United States: wait time to see a physician, length of stay in the emergency department, and the percentage of visits in which patients left before a medical evaluation. Specifically, this appendix presents the following information from the National Center for Health Statistics' (NCHS) National Hospital Ambulatory Medical Care Survey (NHAMCS): for 2003 through 2006 (the only years for which data were available from NCHS), the percentage of emergency department visits by wait time to see a physician (table 12), average and median wait times to see a physician by patient acuity level (figure 6), average wait times to see a physician by payer type, hospital type, and geographic region (table 13), and average wait times by the hospitals' percentage of visits in which patients left before a medical evaluation (table 14); and for 2001 through 2006, the percentage of visits by emergency department length of stay (table 15), the average and median length of stay by patient acuity level (figure 7), the average length of stay in the emergency department by payer type, hospital type, and geographic region (table 16); and average length of stay by the hospitals' percentage of visits in which patients left before a medical evaluation (table 17). In addition to the contact named above, Kim Yamane, Assistant Director; Danielle Bernstein; Susannah Bloch; Ted Burik; Aaron Holling; Carla Jackson; Ba Lin; Jeff Mayhew; Jessica Smith; and Jennifer Whitworth made key contributions to this report.

Summary:
Hospital emergency departments are a major part of the nation's health care safety net. Of the estimated 119 million visits to U.S. emergency departments in 2006, over 40 percent were paid for by federally-supported programs. These programs--Medicare, Medicaid, and the State Children's Health Insurance Program--are administered by the Department of Health and Human Services (HHS). There have been reports of crowded conditions in emergency departments, often associated with adverse effects on patient quality of care. In 2003, GAO reported that most emergency departments in metropolitan areas experienced some degree of crowding (Hospital Emergency Departments: Crowded Conditions Vary among Hospitals and Communities, GAO-03-460). For example, two out of every three metropolitan hospitals reported going on ambulance diversion--asking ambulances to bypass their emergency departments and instead transport patients to other facilities. GAO was asked to examine information made available since 2003 on emergency department crowding. GAO examined three indicators of emergency department crowding--ambulance diversion, wait times, and patient boarding--and factors that contribute to crowding. To conduct this work, GAO reviewed national data; conducted a literature review of 197 articles; and interviewed officials from HHS and professional and research organizations, and individual subject-matter experts. Emergency department crowding continues to occur in hospital emergency departments according to national data, articles we reviewed, and officials we interviewed. National data show that hospitals continue to divert ambulances, with about one-fourth of hospitals reporting going on diversion at least once in 2006. National data also indicate that wait times in the emergency department increased, and in some cases exceeded recommended time frames. For example, the average wait time to see a physician for emergent patients--those patients who should be seen in 1 to 14 minutes--was 37 minutes in 2006, more than twice as long as recommended for their level of urgency. Boarding of patients in the emergency department who are awaiting transfer to an inpatient bed or another facility continues to be reported as a problem in articles we reviewed and by officials we interviewed, but national data on the extent to which this occurs are limited. Moreover, some of the articles we reviewed discussed strategies to address crowding, but these strategies have not been assessed on a state or national level. Articles we reviewed and individual subject-matter experts we interviewed reported that a lack of access to inpatient beds continues to be the main factor contributing to emergency department crowding, although additional factors may contribute. One reason for a lack of access to inpatient beds is competition between hospital admissions from the emergency department and scheduled admissions--for example, for elective surgeries, which may be more profitable for the hospital. Additional factors may contribute to emergency department crowding, including patients' lack of access to primary care services or a shortage of available on-call specialists. In commenting on a draft of this report, HHS noted that the report demonstrates that emergency department wait times are continuing to increase and frequently exceed national standards. HHS also provided technical comments, which we incorporated as appropriate.