Impact of community rating and open enrollment on a prepaid group practice.
D000553:Ambulatory Care; D003365:Costs and Cost Analysis; D003695:Delivery of Health Care; D004608:Eligibility Determination; D006123:Group Practice; D006279:Health Maintenance Organizations; D006296:Health Services / Q000706:statistics & numerical data*; D006760:Hospitalization; D006801:Humans; D007354:Insurance, Major Medical; D014922:Wisconsin