Traditional Chinese Medicine Constitution Identification Based on Objective Facial and Tongue Features: A Delphi Study and a Diagnostic Nomogram for Blood Stasis Constitution

Figure 1

Predictor selection using the least absolute shrinkage and selection operator (LASSO) logistic regression model. (a) Tuning parameter (λ) selection in the LASSO model used 10-fold cross-validation. The area under the receiver operating characteristic (AUC) curve was plotted versus log (λ). Dotted vertical lines were drawn at the optimal values by using the maximum criteria and the 1 standard error of the maximum criteria (the 1-SE criteria). (b) LASSO coefficient profiles of the 14 feature indicators. The dotted vertical line was plotted at the value selected using 10-fold cross-validation in figure (a). For the 1-SE criteria, the optimal λ resulted in six nonzero coefficients.

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