Leakage-Audit Writeup

# Submission: Leakage-Audit Writeup ## Brief Audit the leaky starter notebook (trap: date + id columns leak the target), fix it, and re-score. Show the before/after delta. ## Dataset Same housing split; leaky starter notebook provided with date + id features. ## Starter guardrails (88) - Audit template: suspect list -> ablation table -> fix -> re-score. - Do not delete cells; append the fix so the delta is reviewable. ## Deterministic checks Holdout delta direction correct (leaky train-holdout gap collapses after fix); ablation numbers recompute. ## 100-pt rubric - Suspect identification (date + id + reasoning): 25 - Ablation evidence per suspect: 25 - Correct fix (drop/group + pipeline): 20 - Before/after scoring honesty: 15 - Writeup clarity: 15