# Data audit

• data/schools.csv SHA-256 0f1d8378fff2f0898762feaa08dd94d9ad04156dad6330572d98997c9005c88a (matches bundle.json)
• 1000 rows × 4 columns: school_id (int, 100–139), student_id (int, 1–1000, unique), treated (int 0/1), score (float, points, 35.72–64.17, mean 50.80, sd 4.48).
• Missing values: 0 in every column. Exact duplicates: 0. Duplicate student_id: 0.
• 40 schools, all with exactly 25 students (balanced). treated constant within every school; 20 treated / 20 control schools.
• No dates (no chronology). No anomalies detected; no availability-rule violations (single permitted input).
• Exclusions: none needed (ledger in out/exclusions.csv, all steps remove 0).