Figure 4.

Decision tree for predicting CPO perirectal colonization at hospital unit admission. The gray-shaded terminal node indicates that the tree would classify patients as CPO-colonized, and accompanying percentages reflect the probability that patients assigned to a given terminal node are CPO-positive. Terminal node numbering, 1 through 2, is included in parentheses. The tree had an area-under-the-curve (C-Statistic) of 0.58, which was unchanged in cross-validation. Its sensitivity and specificity were 16.7% and 99.8%, respectively, and its positive and negative predictive values were 54.5% and 99.0%, respectively.