To better compare model performance within clinical categories, we classified all nondiabetic women (n = 26927) into 4 risk groups defined by the ATP III categories of 10-year risk for CVD of 0% to less than 5%, 5% to less than 10%, 10% to less than 20%, and 20% or greater. We then compared the WHS models with and without hsCRP by cross-classifying expected risks and comparing these to the observed proportions of events in each group. While there was general agreement between these classifications (weighted κ= 0.86), the predicted risk categories changed substantially with the addition of hsCRP for women with at least a 5% 10-year risk according to only the Framingham risk variables (Table 3). Specifically, more than 20% of all participants with intermediate risk were reclassified with the addition of hsCRP; among those originally classified as having 5% to less than 10% risk, 12% moved down a category in risk and 10% moved up. Among those originally classified as having 10% to less than 20% risk, 19% were reclassified: 14% to a lower and 5% to a higher category. Among those at high risk (≥20% risk), 14% were reclassified into a lower-risk category. By contrast, among those with less than 5% risk according to Framingham covariables, only 2% were reclassified. Thus, overall in this low-risk cohort, with 88% of women in the lowest risk group, 4% were reclassified. However, this overall percentage depends heavily on the underlying risk and would be substantially greater in an older or higher-risk population. For comparison, according to ATP III risk categories based on National Cholesterol Education Program β-coefficients rather than those derived from the WHS, among women originally classified as having less than 5%, 5% to less than 10%, 10% to less than 20%, and 20% or greater 10-year risk, 4%, 38%, 42%, and 20%, respectively, were reclassified in the WHS model that included hsCRP.