1[2 {"id":"C1","text":"The OLS Okun coefficient over 1960Q1-2019Q4 (n=240) is about -0.256 pp of unemployment per 1% quarterly real GDP growth, with intercept 0.184 and R^2 0.408.","results_keys":["beta_hat","alpha_hat","r_squared","n_analysed","first_quarter","last_quarter"],"status":"supported","caveat":"Contemporaneous linear projection; not causal; current-vintage data."},3 {"id":"C2","text":"The Newey-West (Bartlett, 4 lags) HAC standard error is 0.0358, about 1.8 times the naive iid SE of 0.0200, reflecting positively autocorrelated residuals.","results_keys":["se_hac","se_iid","hac_lags","resid_autocorr_lag1_4"],"status":"supported","caveat":"Bandwidth from the Newey-West (1994) rule of thumb."},4 {"id":"C3","text":"The Okun coefficient is negative and significantly different from zero at the 5% level using the HAC SE; 95% CI [-0.326, -0.186].","results_keys":["okun_negative_5pct","beta_ci_low","beta_ci_high","t_hac","p_value_hac"],"status":"supported","caveat":"Normal critical values; asymptotic HAC inference."},5 {"id":"C4","text":"The significance conclusion is robust to HAC bandwidths from 0 to 12 lags.","results_keys":["sensitivity_se_hac_by_lag","beta_hat"],"status":"supported","caveat":"Only Bartlett kernel examined."},6 {"id":"C5","text":"Mean quarterly real GDP growth over the sample is 0.754%.","results_keys":["mean_growth"],"status":"supported","caveat":"Log growth, not annualised."}7]8