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.