Fig. 2From: Ensemble learning-assisted prediction of prolonged hospital length of stay after spine correction surgery: a multi-center cohort studyFeature selection and fivefold cross-validation technique. a Boruta result plot for training data. Blue boxplots correspond to minimal, average, and maximum Z score of a shadow attribute. Red and green boxplots represent Z scores of, respectively, rejected and confirmed attributes. b Accuracy lines plot of nine ML algorithms through fivefold cross-validationBack to article page