Fig. 2: Visualization of covariate shift in the eICU and MIMIC-III dataset.

a–d Distribution differences in patient demographics, calculated as the proportion of patients in each demographic group within each hospital. Note: The Caucasian group was excluded from panel b to enhance the visibility of minority group distributions, as its majority presence would otherwise dominate the color scale and mask smaller variations. e–g In-hospital and out-hospital distribution by ML-based density estimators. For each hospital, the in-hospital estimate was calculated by applying its own density estimator to its patient data. The out-hospital estimate was computed by applying the same density estimator to patient data from a different hospital.