A history of public health workforce enumeration.

During the 20th century, the United States' public health workforce has been of sufficient interest to policy makers that regular efforts have been made to enumerate it. Limited enumeration is found as early as 1908; the last direct federal survey occurred in 1964. After 1964, workforce size was estimated. The ratio of public health workers to population reached an estimated 220/100,000 in 1980. Data collected in 2000 yielded a ratio of 158/100,000--a 10 percent decrease. In the absence of a system to reliably collect public health workforce data such information is problematic to interpret or use for infrastructure planning and development.