Use of case-control studies for the evaluation of preventive health care.
D002986:Clinical Trials as Topic; D005069:Evaluation Studies as Topic; D006302:Health Services Research / Q000379:methods*; D006801:Humans; D007114:Immunization / Q000592:standards; D008403:Mass Screening / Q000592:standards; D011314:Preventive Health Services / Q000592:standards*; D011897:Random Allocation