Stepwise forward logistic regression was used to identify combinations of symptom measures that differentiated children with and without viral URIs. The final regression model included all candidate symptom measures associated with the outcome of viral URI (p Ͻ 0.30). To develop a "URI symptom score," 1 point was given for the presence of each of the identified symptom measures; the total URI symptom score in a given patient was the sum of these points. Receiver-operating-characteristic (ROC) analysis was done to choose the cut-off score that maximized the accuracy of the cold score in predicting the presence of a viral URI. "Accuracy" was defined as the proportion of children with a viral URI with a "positive" URI symptom score plus the proportion with no URI with a negative score.