1[2 {"id":"C1","text":"The OLS Okun coefficient for 1960Q1-2019Q4 (240 quarters, quarter-on-quarter non-annualised growth) is about -0.256 with intercept 0.184 and R-squared 0.408.","results_keys":["beta_hat","alpha_hat","r_squared","n_analysed","first_quarter","last_quarter"],"status":"supported","caveat":"Descriptive linear projection, not causal; current-vintage data."},3 {"id":"C2","text":"The Newey-West (Bartlett, 4 lags) HAC standard error is 0.0358, giving a 95% CI of [-0.326, -0.186]; the bandwidth follows the floor(4(T/100)^(2/9)) rule.","results_keys":["se_hac","hac_lags","beta_ci_low","beta_ci_high","hac_lags_rule_nw1994","hac_lags_rule_sw"],"status":"supported","caveat":"Asymptotic normal critical values, no df correction."},4 {"id":"C3","text":"The Okun coefficient is negative and significantly different from zero at the 5% level using the HAC SE.","results_keys":["okun_negative_5pct","t_stat_hac","p_value_hac"],"status":"supported","caveat":"Two-sided test, normal approximation."},5 {"id":"C4","text":"The HAC SE is about 1.8 times the naive iid SE, consistent with positive residual autocorrelation.","results_keys":["se_hac","se_iid","resid_autocorr_lag1_4","baseline_ci_iid_low","baseline_ci_iid_high"],"status":"supported","caveat":"Ratio computed from the two reported SEs."},6 {"id":"C5","text":"Significance does not depend on the bandwidth: across 0-12 lags the HAC SE stays at or below 0.0371 and p-values stay at or below 5.7e-12.","results_keys":["se_hac_max_over_lags_0_12","p_value_hac_max_over_lags_0_12"],"status":"supported","caveat":"Bartlett kernel only."},7 {"id":"C6","text":"Mean quarterly real GDP growth over the sample is 0.754% (about 3.0% annualised), and the growth rate consistent with a stable unemployment rate is about 0.72% per quarter.","results_keys":["mean_growth","alpha_hat","beta_hat"],"status":"supported","caveat":"The stable-unemployment growth rate is derived as -alpha_hat/beta_hat."}8]9