Siegel, D. G., and S. W. Greenhouse (Nat. Inst Child Health and Human Development, NIH, Bethesda, Md. 20014.) Multiple relative risk functions in case-control studies. Am J Epidemiol 97: 324–331, 1973.—In case-control studies in which the risk of disease in the population is unknown, multiple relative risk functions similar to the multiple risk functions used in cohort studies can be obtained. This was demonstrated for two population modeLs, the linear discrimination model and the linear multiple regression model. In the first model ratios of odds are yielded; in the second model the ratios of risks can be obtained if the risks themselves are small.