Usmile - Threshold-Free Class-Specific Comparison of Binary Classifiers

Implements the U-smile methodology for threshold-free, class-specific comparison of probabilistic binary classifiers. The package quantifies prediction improvement and worsening separately for non-events and events using the Brier alteration (BA), relative Brier (RB), improvement proportion (I) coefficients, and relative likelihood ratio (rLR) coefficients, and provides U-smile, prediction improvement-worsening, receiver operating characteristic, and precision-recall plots. The original U-smile framework is described in Kubiak et al. (2024) <doi:10.1371/journal.pone.0303276>, its three-level extension for imbalanced binary classification in Wieckowska et al. (2025) <doi:10.1371/journal.pone.0321661>, and the likelihood-based extension in Wieckowska and Guzik (2026) <doi:10.1038/s41598-026-40545-z>.