1[2 {"id":"C1","text":"Over 1960Q1-2019Q4 (n=240), OLS gives an Okun coefficient of about -0.256: 1 pp higher quarterly real GDP growth goes with a 0.26 pp smaller quarterly change in unemployment.","results_keys":["beta_hat","alpha_hat","r_squared","n_analysed","first_quarter","last_quarter"],"status":"supported","caveat":"This is a linear projection on current-vintage data, not a causal estimate. Parameter stability over time was not tested."},3 {"id":"C2","text":"With a Newey-West Bartlett HAC SE (4 lags), the coefficient is negative and significant at 5%. The 95% CI is [-0.326, -0.186].","results_keys":["se_hac","hac_lags","beta_ci_low","beta_ci_high","okun_negative_5pct"],"status":"supported","caveat":"Inference relies on the asymptotic normal distribution. The conclusion holds for bandwidths from 0 to 12 lags."},4 {"id":"C3","text":"The naive i.i.d. SE (0.020) understates the uncertainty: the HAC SE (0.036) is about 1.8 times larger, because the residuals are positively autocorrelated.","results_keys":["se_iid","se_hac"],"status":"supported","caveat":"The residual autocorrelations are in out/diagnostics.json, not in results.json."}5]6