Fig. 15
PR curve comparison across five-fold cross-validation for multi-level fall risk classification. One-vs-rest precision–recall (PR) curves for the four safety levels obtained from 5-fold stratified cross-validation. Each subplot corresponds to one class, and PR curves are computed from predicted class probabilities. Due to the limited number of positive samples per fold (25 positives per class, given 125 samples per class in total), the PR curves exhibit a step-like appearance with discrete recall levels. The horizontal dashed line denotes the random classifier baseline, defined by the positive class prevalence (0.25). Colored curves indicate results from individual folds, and AUPRC trends are consistent with the class-wise confusion matrix analysis.
