Miettinen, O. S. (Harvard School of Public Health, Boston, Mass. 02115). Components of the crude risk ratio. Am J Epidemiol 96: 168–172, 1972.—BothBoth in cohort and case-control studies the estimate of the crude risk ratio factors into two important and easily derived components. One is a measure of the strength of confounding, and the other is an estimate of the residual risk ratio in terms of the standardized morbidity (mortality) ratio. For case-control studies the latter seems to be a new and useful “summary relative risk.”