# Contract — F1-conf-03
**Question:** association between end-of-year-t leverage and default in t+1, using only info known at end of t.
**Estimand:** b1 (coef on leverage) in OLS LPM default_next ~ 1 + leverage + cash_ratio + log_sales, on firm-years with observed default_next; SEs clustered by firm_id. Meaningful as a conditional association (not causal); LPM assumes linear conditional mean; cluster SEs assume independence across firms and enough clusters (~300).
**Outputs:** out/results.json (task_id, n_analysed, n_firms, predictors_used, variables_excluded, beta_leverage, se_leverage_cluster, r2, default_rate, feasibility, feasibility_reason, data_issues, n_input_rows, random_seed); out/analytic.csv; out/exclusions.csv; out/report.md (6 sections); out/analysis.py; out/claims.json.
**Information rules:** only predictors known at end of t (leverage, cash_ratio, log_sales). rating_2025 is known in 2025 and built from realised defaults -> leakage, must be excluded and listed. Rows with missing default_next excluded and logged, never imputed. Only data/firm_panel.csv.
**Invalidating:** using rating_2025; imputing outcomes; duplicate rows double counting; no observed outcomes.