The Penn State Workforce Education and Development Initiative (WEDI) conducted an analysis of the economic impact of ambulatory health care services in Pennsylvania in the first part of a three-part series of analyses of the economic impact of jobs in the health care sector. Subsequent analyses will be released, next, about the impact of jobs in hospitals and, then, in nursing and residential care facilities in the Commonwealth.Ambulatory health care services are provided by physicians, dentists, and other health care practitioners. These services are performed at outpatient clinics, urgent care centers, emergency rooms, ambulatory or same-day surgery centers, diagnostic and imaging centers, primary care centers, community health centers, occupational health centers, mental health clinics, and group practices.Rapid growth of ambulatory health care services since the 1980s has been fueled by cost controls sought by insurers and governments. These controls seem to have had an effect on costs. For example, medical procedures performed in an outpatient surgery center typically costs 30% to 60% less than the same procedures conducted in an inpatient hospital setting. Also, advances in surgical techniques have reduced the need for hospital stays for recovery. An added benefit is that many patients find recovery at home more convenient and less stressful than in a hospital. Many ambulatory health care services are provided directly in the offices of health practitioners, where facilities and equipment are less prominent in the delivery of services than in outpatient diagnostic, treatment, and surgical centers.The ambulatory health care services industry employed 324,929 workers in 22,599 Pennsylvania establishments during 2008. Approximately one–half of these workers were employed in seven of Pennsylvania's 67 counties (in order: Allegheny; Philadelphia; Montgomery; Bucks; Delaware; Lehigh; and Chester). The industry grew by 40,350 Pennsylvania workers between 2004 and 2008. Average annual earnings per worker in the industry were $62,773 in 2008, although earnings differed significantly by occupation. For instance, on average, the state's 31,494 physicians earned $65.03 per hour worked, while 21,926 registered nurses earned $28.69 per hour and 18,088 medical assistants earned $12.94 per hour. In contrast, 15,041 home health aides working in the ambulatory health care services industry earned an average of $9.86 per hour, which is pennies above the poverty wage for a household composed on two adults and two children in Pennsylvania (cf., Poverty Thresholds for 2007 by Size of Family and Number of Children). The living wage for a one–adult household in Pennsylvania is considered to be $8.00 per hour. The living wage is defined as the hourly wage rate that an individual must earn to support a family, if the individual is the sole provider and is a full–time worker (2080 hours per year). The living wage varies by the number of dependents an individual supports as well as by the region in which the individual resides. Ambulatory health care services are classified in North American Industrial Classification System code 621. According to the U.S. Bureau of the Census, establishments in this industry health care services directly or indirectly to ambulatory patients and do not usually provide inpatient services. During 2007, 5.8 million U.S. workers were employed in the ambulatory health care industry in 547,000 establishments with an annual payroll of $285 billion.