nant of patient survival has been confirmed (Smith et al., 1990; Konvolinka et al., 1995). Still, there is no consensus on the amount of patient volume necessary for optimal performance of a trauma center (Moore, 1995).
More than 30 years ago, the National Research Council (NRC, 1966) spotlighted the paucity of trained emergency personnel at every level of care. The growth in the number of prehospital providers and the increase in their level of training are among the major achievements of the past three decades. The number of prehospital providers is estimated today at about 650,000 nationwide (W.E. Brown, National Registry of Emergency Medical Technicians, personal communication, 1998). Accompanying this growth has been the creation and standardization of the prehospital curriculum. Since the enactment of the 1966 Highway Safety Act, NHTSA has spearheaded the development of standardized curricula for multiple types of prehospital personnel (U.S. DOT, 1996b). In a series of evaluations conducted from 1988 to 1994, NHTSA found that 72.5 percent of 40 states used standardized curricula (primarily NHTSA's) in training courses for prehospital providers (U.S. DOT, 1995). NHTSA's FY 1997 budget for the EMS division responsible for curriculum development is $1.5 million. By virtue of its leadership and support for prehospital training and state highway grants, NHTSA is the federal agency with the most consistent and long-standing presence in trauma systems development (U.S. DOT, 1996b).
Certification of prehospital providers also has progressed, with all 50 states having some kind of certification procedure (BLS, 1997). However, there is much variability in requirements for certification (U.S. DOT, 1996b). Thirty-nine states certify prehospital providers who have passed written and practical examinations administered by the National Registry of Emergency Medical Technicians, a nonprofit certifying organization (NREMT, 1998). Yet, most states do not adhere to the registry's biennial reregistration requirement. Less than one quarter of the estimated 650,000 emergency medical technicians (EMTs) nationwide maintained their registration as of November 1997 (W.E. Brown, National Registry of Emergency Medical Technicians, personal communication, 1998).
There also has been considerable growth in the field of emergency medicine. The first emergency medicine residency program was formed in 1970. By 1998, the number of accredited residency programs had expanded to 120 (M. Schropp, Society for Academic Emergency Medicine, personal communication, 1998). The first certifying examination was given in 1980, one year after emergency medicine was recognized as a specialty by the American Medical Association Committee on Medical Education and the American Board of Medical Specialties. The number of board-certified emergency physicians catapulted to 15,202 by 1997 (American Board of Emergency Medicine, personal communi-