title: Physician scarcity is a predictor of further scarcity in US, and a predictor of concentration in Japan.
abstract: OBJECTIVE
  To assess the effects of geographic diffusion of physicians from medically oversupplied toward undersupplied areas driven by economic competition among physicians and political interventions in Japan and US.
  
  
  METHODS
  A quantitative evaluation of physician workforce changes at the community level between 1980 and 2005, using municipality-based (Japan) and county-based (US) census data.
  
  
  RESULTS
  The overall number of physicians per 100,000 population (physician-to-population ratio: PPR) increased from 130 to 203 in Japan and 158 to 234 in US. In this context, a higher proportion (30.1%) of the quintile communities with lowest PPRs in 1980 has further decreased their PPRs in US than in Japan (21.6% in 2005). In multivariate analysis low PPR was a positive predictor of PPR decrease in the US communities (odds ratio 1.26; 95% confidence interval 1.01-1.58), while it was a negative predictor in Japanese communities (0.69; 0.57-0.83).
  
  
  CONCLUSIONS
  Physician scarcity is associated with further scarcity in US communities, while scarcity is associated with recovery from scarcity in Japanese communities. Competition-based physician diffusion strategies and various interventions to address the maldistribution of physicians apparently have not worked effectively in US compared with Japan.
authors.affiliation: Division of Community and Family Medicine, Centre for Community Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan. matmo10@jb3.so-net.ne.jp
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Kazuo
authors.initials: K
authors.lastname: Inoue
authors.forename: Robert
authors.initials: R
authors.lastname: Bowman
authors.forename: Satomi
authors.initials: S
authors.lastname: Noguchi
authors.forename: Eiji
authors.initials: E
authors.lastname: Kajii
mesh_terms: D019352:Censuses; D016009:Chi-Square Distribution; D003710:Demography; D004465:Economic Competition; D005544:Forecasting; D006302:Health Services Research; D006801:Humans; D007564:Japan; D016015:Logistic Models; D008389:Marketing of Health Services; D008507:Medically Underserved Area; D015999:Multivariate Analysis; D010561:Personnel Staffing and Scheduling; D010820:Physicians / Q000191:economics / Q000600:supply & distribution* / Q000639:trends*; D011057:Politics; D011156:Population Density; D011365:Professional Practice Location / Q000191:economics / Q000639:trends*; D012959:Socioeconomic Factors; D014481:United States