# Log

• 2026-10-30 P0 passed: contract written.
• 2026-10-30 P1: audited all 10 inputs; SHA-256 match README; no missing/duplicates/gaps.
• 2026-10-30 Decision (made before computing any out-of-sample error): model = AR(1) with intercept, OLS, estimation window 1985Q1 to the last quarter of the origin vintage, dropping regression observations whose dependent quarter is 2020Q2, 2020Q3 or 2020Q4 (COVID outliers -28/+35 % SAAR as dependent or lagged regressor); 2-step forecast by iteration. Rationale: Great Moderation era stable dynamics; COVID quarters would dominate OLS.
• 2026-10-30 P2/P3 passed (naive baseline + AR(1)); P4 passed (reproducible, all checks PASS); P5 passed (report, claims).