Table 2. Comparison of 17 ileal gene signatures selected by four different feature selection methods.

Methods	AUC	Accuracy
Boosting	0.928	89.9%
PAM	0.895	88.9%
Random forest	0.902	85.9%
LASSO	0.895	85.9%

Boosting [16], PAM) [17], random forest [18] and LASSO [19] were applied to the SAM filtered training microarray dataset to select 17 ileal gene signatures. The AUC and overall accuracy for each of the signatures were calculated based on the majority vote of 7 classifiers (Boosting, PAM, Random Forest, LASSO, Support Vector Machine, Linear Discriminant Analysis, and Naive Bayes), which is equivalently to the decision based on the median score using an usual probability threshold of 0.5 (see Materials and Methods).