Table 5.

Risk Group Statistics for the Models Built Using the Patient Data

Derivation groupValidation group
Flu/Total (%)LRIn Group (%)Flu/Total (%)LRIn Group (%)
LASSO score
 Low0/5 (0.0)0.02.90/0 (NA)NA0.0
 Moderate20/77 (26.0)0.344.316/34 (47.1)0.845.3
 High68/92 (73.9)2.852.923/41 (56.1)1.254.7
Conditional inference tree (manual)
 Low1/32 (3.1)0.018.45/12 (41.7)0.715.8
 Moderate6/25 (24.0)0.314.46/14 (42.9)0.718.4
 High81/117 (69.2)2.267.228/50 (56.0)1.265.8
Naive Bayes classifier
 Low0/0 (NA)NA0.00/0 (NA)NA0.0
 Moderate0/7 (0.0)0.04.00/4 (0.0)0.05.3
 High88/167 (52.7)1.196.039/72 (54.2)1.194.7
  • Abbreviations: LASSO, Least Absolute Shrinkage and Selection Operator; LR, stratum-specific likelihood ratio.

  • Notes: The models were trained using the derivation set of clinician-reported symptom data, and evaluated on both the derivation and validation sets separately. We obtained quantitative risk predictions for each individual from the models, and assigned individuals with a risk less than 10% to the low risk group, individuals with a risk between 10% and 50% to the moderate risk group, and individuals with a risk greater than 50% to the high risk group.