Your vaccination-lift experiment shows no overall effect and a negative effect in seniors. Lay out a triage plan: (a) exposure verification (deliverability, inbox placement, opens/clicks under mail privacy protections), (b) targeting leakage/crossover and contamination checks, (c) logging/ETL audits for timestamp/timezone/dedup errors, (d) outcome validity (claims/EHR coverage gaps and lag from shot to claim), (e) lift suppressors (fatigue, frequency-capping bugs, creative rendering issues), (f) heterogeneity and calendar interactions, (g) re-test design (A/A, split-by-seed, staggered rollouts) and quick corrective experiments, and (h) decision criteria to pause, pivot, or proceed. Specify example queries/plots you would run and the minimal additional data you would request.