# Contract — F1-conf-01

Question. 12-month % growth of CPIAUCSL (SA) for each month 2001-01..2026-09, g_t = 100(P_t/P_{t-12} − 1), with P from the most recent vintage covering the month (2026-10-28 for 2014-01..2026-09, else 2016-07-15). Estimands. Window mean of g_t; sub-period means 2001-01..2013-12 and 2014-01..2026-09; g_t for 2014-06, 2016-07, 2020-05, 2022-06, 2026-09; max/min g_t and months; counts of computable/missing months. Meaningful as descriptive statistics of published data; for 2014 months g_t mixes vintages by construction of the rule. Outputs. out/results.json (keys per TASK table), out/analytic.csv (date,cpi,cpi_lag12,vintage_used,growth_12m; n_analysed rows), out/exclusions.csv, out/report.md (6 sections), out/analysis.py, out/claims.json. Information rules. Most-recent vintage per month; no interpolation/imputation; missing g_t reported and counted; only data/ files. Invalidating conditions. Using the hand-assembled file uncritically (it may be wrong); imputing the missing level; using old-vintage values where new vintage covers the month. Infeasible only if the vintage files were unusable.