Fig. 1

Box plots of the density of three types of workforce per 10,000 population by county share in province. Note: X axis = 31 provinces. Y axis = density of workforce per 10,000 population. Panel A = description for staff. Panel B = description for health professionals. Panel C = description for field epidemiological investigators. Because of the confidentiality of the data, we have hidden the names of the provinces and used the region code to represent them: E for the eastern provinces, C for the central provinces, and W for the western provinces. According to the range between maximum county density and minimum county density in each province, the provinces are sorted from large to small