The physician assistant (PA) is a global phenomenon: a product of medicine that enjoys unparalleled success within the health profession in many societies. Born in the 1960s, nurtured in the 1970s, and grown in the 1980s, the PA proved to be a capable player in American health policy in the 1990s. By 2000, the PA had emerged in a handful of countries, and by 2015, PAs will surpass 100 000 worldwide.1

Various explanations regarding why this profession is growing have been advanced. Clearly, PAs fit well in the entrepreneurial American health care system; economic advantages, clinical flexibility and dependence on doctors are factors that contribute to their success. But it is other countries that are building on the original model. With a worldwide shortage of 4.5 million doctors and an inadequate number of medical schools, the sheer weight of population growth demands more medical personnel and resources.2 In addition, improvements in childhood survival and the control of archaic diseases (eg, malaria, tuberculosis, dengue fever, smallpox, polio) have resulted in people living longer and more comfortably than their parents. Technological advancements are limited only by the logistics of delivery to populations, both urban and remote.3 The increasing years of productivity of individuals indicates the need for an unprecedented cadre of health workers. Without more doctors and nurses, the next group of providers to look to is PAs. Canada, the United Kingdom, South Africa and the Netherlands are examining not only their present workforces, but also what will be needed in decades to come. The alternative to not growing their own workforces is recruiting overseas-trained doctors — a strategy with its own ethical considerations.4,5

A sociological explanation for the emergence of PAs is an evolution in the division of medical labour, not a loss of autonomy for doctors. Medicine has become infinitely more complex over the past several decades and the information base required to practise medicine is enormous, leading to greater levels of team-based care. Health care knowledge was once a vaunted supremacy of doctors, but now diagnostic and therapeutic tasks are shared with other health care professionals (in part because modern-day doctors cannot know and do everything in so vast a field). Throughout the 20th century, analytical technologies and therapeutic approaches produced new specialties, and today we have genetics, interventional radiology, robotic surgery and the resurgence of midwifery. Further expansion of medical activities and capabilities will necessitate the inclusion of additional trained personnel who share the domains of doctors but remain dependent on doctors for directing care.

Other social forces have had a major influence on the PA movement.

• Changing lifestyles — doctors’ preferences for greater work–life balance grew during the 1970s. Today, most are eager to work (though not as hard as their predecessors) and desire help.

• Gender shifting — women have entered the workforce in a major way. They have tried out careers that are traditionally dominated by men, and have found them to their liking. For PAs, the education path is shorter than for medicine but has similar rewards. The opportunity to be engaged in a well respected career and successfully raise a family ranks high with many female applicants.

• Doctor dependency — the unwavering commitment of the PA profession to remain dependent on doctors bolsters widespread acceptance of PAs by medical professional bodies.

• National competency — the establishment of program accreditation and an independent national board overseeing the specific skills and competencies of PAs allows states to focus on licensure, roles and supervision.

• Primary care — for PAs, the emphasis on training in general medical care and obtaining core competencies creates a known entity. Such a model permits more role flexibility and mobility (beneficial characteristics in a changing health care environment) than exists for doctors and nurse practitioners.

The PA succeeds, in part, because of the attributes of individuals. Early entrants saw themselves as change agents who wanted to prove that allied health individuals trained in this PA model could benefit society safely and effectively. The PA profession continues to attract those who feel dead-ended in their current health care roles but do not want the burden of a protracted medical school experience or investment. For example, an experienced military medic may seek to use his or her skills in civilian life or an indigenous health care worker who is isolated without options for career progression may wish to upgrade his or her role to enable a return to cultural roots.

Looking forward, key questions emerge. What does the future hold for the PA profession? How will the changing faces of various health care systems affect the PA profession? Will a PA trained and certified in Utrecht, the Netherlands, be able to work in Mt Isa, Australia, and be effective? Two phenomena are shaping PAs and their futures: change in human societies and change in health care delivery. These are on convergent paths that predict the growth of PAs for many years to come — at least in many countries. How Australia will fit this new provider into its health care system is contentious for some. For those who want to expand the capacity of its highly skilled workforce, the pace of change leaves few options.6