医師数の需給推計

抄録

This review aims to provide an overview of the conventional methods of projecting the supply and demand for physicians in scientific as well as political contexts, then to summarize four projection studies conducted in Japan, and to draw lessons for the analytic framework and models to be adopted in future research. Referring to Bärnighausen and Bloom (2011), four types of approach are found, namely, the need approach, demand approach, service target approach, and population ratio approaches. These were developed in 60s and 70s, and continue to be applied today. For demand projection, the framework proposed by the Organization for Economic Cooperation and Development sets out five determining factors for physician demand, namely (1) population size, (2) current utilization patterns, (3) change in utilization patterns, (4) changes in health service delivery systems, and (5) GDP/health expenditure growth, all of which except for GDP growth were incorporated into previous studies conducted in Japan. Compared to demand projection, supply projection depends on the entry rate of physicians, which is regulated by the national licensing exam, expected career length, labor participation rate of women physicians, and country-specific factors such as immigration rate and other sources of the medical workforce (e.g. physician assistant). As the review found, the estimated results for the demand/supply projection of physicians are highly dependent on model assumptions that should be selectively adopted based on the context of current healthcare systems, advances in medical technology, measures that secure medical quality, and political factors. It also concludes that future estimations based on the utilization of projected services (e.g., need approach and service target approach) should be undertaken to address changing technologies and health transitions. It concludes that critical and academic arguments over adopted models and assumptions should be encouraged to refine the scientific validity of projections of physician demand/supply in Japan.