Expose issues early. Validate fairly. Trust what you ship.
Validation prevents surprises in production. Check for leaks, bias, drift, and weak signals before you deploy.
| Feature | |corr| | Risk |
|---|
A single feature that correlates almost perfectly with the target is often leakage. This is the intuition behind audit().
Potential leakage detected
3 features may contain target leakage or post-outcome information.
| Feature | Risk |
|---|---|
days_since_last_contact Occurs after churn | 0.92 |
support_tickets_30d Leakage window | 0.81 |
churn_flag Direct target proxy | 0.99 |
Moderate drift detected vs training data.
Model A vs Model B (XGBoost vs LightGBM)
At alpha = 0.05, the performance difference is statistically significant.
| Metric | A | B |
|---|---|---|
| ROC AUC | 0.912 | 0.907 |
| Diff | +0.005 | |
Intended use
Predict customer churn in subscription business to support retention outreach.
Training data
Churn v1 (Train), 2025-04-01 to 2025-05-31.
Next: cross the Bridge. An honest model deserves a clean path to production.
Continue to the Bridge