of paramedicine, a great deal of both curriculum and skill set was in a state of constant flux. Permissible skills evolved in many cases at the local level, and were based upon the preferences of physician advisers and medical directors. Treatments would go in and out of fashion, and sometimes, back in again. The use of certain drugs, Bretylium for example, illustrate this. In some respects, the development seemed almost faddish. Technologies also evolved and changed, and as medical equipment manufacturers quickly learned, the pre-hospital environment was not the same as the hospital environment; equipment standards that worked fine in hospitals could not cope well with the less controlled pre-hospital environment. Physicians began to take more interest in paramedics from a research perspective as well. By about 1990, most of the 'trendiness' in pre-hospital emergency care had begun to disappear, and was replaced by outcome-based research and evidence-based medicine; the gold standard for the rest of medicine. This research began to drive the evolution of the practice of both paramedics and the emergency physicians who oversaw their work; changes to procedures and protocols began to occur only after significant outcome-based research demonstrated their need. Paramedics became increasingly accountable for their errors as well, and these too led to changes in procedure. Such changes affected everything from simple procedures, such as CPR, to changes in drug protocols and other advanced procedures. As the profession of paramedic grew, some of its members actually went on to become not just research participants, but researchers in their own right, with their own projects and journal publications. Education The education and skills required of paramedics vary by state. The U.S. National Highway Traffic Safety Administration (NHTSA) designs and specifies a National Standard Curriculum for EMT training. Most paramedic education and certifying programs require that a student is at a minimum educated and trained to the National Standard Curriculum for a particular skill level. The National Registry of Emergency Medical Technicians (NREMT) is a private, central certifying entity whose primary purpose is to maintain a national standard. NREMT also provides certification information for paramedics who relocate to another state. Paramedic education programs can be as short as six months or as long as four years. An associate degree program is two years, often administered through a community college. Degree programs are an option, with two-year associate degree programs being most common, although four-year bachelor's degree programs