Churn / LTV Case Defense (Calibration -> Decision)

# Churn / LTV Case Defense (Calibration -> Decision) Defend the threshold policy: from calibrated probabilities to a business action. ## 1. Calibration before thresholds PR-AUC + Brier score on holdout; reliability curve in the appendix. An uncalibrated ranker cannot set a money threshold — say this out loud first. ## 2. Cost-matrix threshold False-positive cost (wasted retention offer) vs false-negative cost (lost customer LTV). Threshold = argmin expected cost, shown as a one-table sweep — not 0.5 by default. WE W3-W4 is the reference framing. ## 3. SHAP story in 3 slides Top-5 drivers with direction, one slice where the model is weakest, one action per slice. Calibration -> threshold -> story is the defense spine.