What problem does it solve? Standard machine learning libraries cannot handle censored survival data where some subjects never experience the event during observation. This Skill guides you through time-to-event modeling with scikit-survival, from data preparation through model fitting and proper evaluation. ## Core Features & Use Cases - Multiple Model Families: Fit Cox proportional hazards models (standard and penalized Coxnet), Random Survival Forests, Gradient Boosting, and Survival SVMs depending on data size and interpretability needs. - Censoring-Aware Evaluation: Compute Harrell's and Uno's concordance index, time-dependent AUC, and integrated Brier score with correct handling of censored observations. - Competing Risks & Non-parametric Estimation: Estimate cumulative incidence functions for multiple event types, plus Kaplan-Meier and Nelson-Aalen curves. - Use Case: Given a clinical dataset with patient follow-up times and event indicators, build a Gradient Boosting survival model, tune it with cross-validation using the IPCW concordance scorer, and report Uno's C-index and integrated Brier score on held-out patients. ## Quick Start Ask the AI to fit a Cox proportional hazards model on your survival dataset and evaluate it with Uno's concordance index.