[
 {"id":"C1","text":"Over 1960Q1-2019Q4 a 1% higher quarterly real GDP growth is associated with a 0.256 pp lower change in the unemployment rate; the 95% HAC CI [-0.326,-0.186] excludes zero.","results_keys":["effect_estimate","effect_se","hac_lags","effect_ci_low","effect_ci_high","conclusion"],"status":"supported","caveat":"Reduced-form association, not causal; revised-vintage data."},
 {"id":"C2","text":"The Okun regression improves on the mean-only baseline (RMSE 0.250 vs 0.325 pp).","results_keys":["model_metric","baseline_metric"],"status":"supported","caveat":"In-sample fit only."},
 {"id":"C3","text":"The classical Chow test rejects joint equality of (alpha, beta) across 1960-83 and 1984-2019 at 5% (F=6.09, p=0.0026).","results_keys":["chow_f_stat","chow_p_value","stability_conclusion"],"status":"supported","caveat":"Classical test assumes iid errors (residuals autocorrelated); HAC Wald version (robustness.json) also rejects, p=0.004."},
 {"id":"C4","text":"The subperiod slopes are nearly identical (-0.259 vs -0.273); the instability reflects the intercept/break-even growth rate rather than beta.","results_keys":["beta_sub1","beta_sub2","n_sub1","n_sub2"],"status":"supported","caveat":"Slope-difference test (HAC p=0.85) and break-even growth are in out/robustness.json, not results.json; failing to reject is not proof of equality."}
]