Supported a feasibility assessment using real-world data in Germany for an observational study in breast cancer chemoprevention. Engineered cohort identification logic for eligible patients using diagnosis code groupings, implemented lookback/history evaluation scenarios, and developed extraction logic for key high-risk variables (e.g., family history proxies, BMI, alcohol intake, hormone therapy, oral contraception). Built treatment exposure datasets for tamoxifen, including dosage characterization, prescription frequency, daily dose estimation, dose group classification, and dose switching/wash-out analyses to inform study design recommendations.