This article addresses a potentially serious problem with the widely used self-rated health (SRH) survey item: that different groups have systematically different ways of using the item's response categories. Analyses based on unadjusted SRH may thus yield misleading results. The authors evaluate anchoring vignettes as a possible solution to this problem. Using vignettes specifically designed to calibrate the SRH item and data from the Wisconsin Longitudinal Study (WLS; N = 2,625), the authors show how demographic and health-related factors, including sex and education, predict differences in rating styles. Such differences, when not adjusted for statistically, may be sufficiently large to lead to mistakes in rank orderings of groups. In the present sample, unadjusted models show that women have better SRH than men, but this difference disappears in models adjusting for women's greater health-optimism. Anchoring vignettes appear a promising tool for improving intergroup comparability of SRH. (Contains 9 notes, 7 tables, and 2 figures.)