Validation of the Cox model involves several steps: 1. Assessing Proportional Hazards Assumption: This can be done using graphical methods like Schoenfeld residuals or statistical tests. 2. Goodness-of-Fit: Techniques such as the Likelihood Ratio Test, Wald Test, and Score (Log-Rank) Test are used. 3. Model Diagnostics: Checking for influential data points and outliers using residual plots and other diagnostic tools.
