title: The validity of nonexperimental designs for evaluating health services.
mesh_terms: D000328:Adult; D000367:Age Factors; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000517:prevention & control*; D003153:Community Health Services; D004812:Epidemiologic Methods; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008824:Michigan; D008875:Middle Aged; D012107:Research Design; D012737:Sex Factors; D013223:Statistics as Topic; D013997:Time Factors
chemical_list: D000893:Anti-Inflammatory Agents