Health care costs in health maintenance organizations: correcting for self-selection.
D003256:Community Participation; D003365:Costs and Cost Analysis; D006123:Group Practice / Q000706:statistics & numerical data*; D006125:Group Practice, Prepaid / Q000706:statistics & numerical data*; D006279:Health Maintenance Organizations / Q000706:statistics & numerical data*; D006302:Health Services Research; D006304:Health Status; D008962:Models, Theoretical; D012044:Regression Analysis; D014481:United States; D014861:Washington