1[2 {"id":"C1","text":"Over 60 origins (2021-09 to 2026-08), the ridge forecast has RMSE 0.561 vs 0.883 for the naive forecast, a 36.5% relative improvement.","results_keys":["rmse_ridge","rmse_naive","rel_improvement_vs_naive"],"status":"supported","caveat":"Current-vintage data, publication lags ignored; DM p=0.0014 (uncertainty.json)."},3 {"id":"C2","text":"The ridge forecast does not beat the expanding historical mean: RMSE 0.561 vs 0.544 (relative improvement -3.1%), and MAE is also higher.","results_keys":["rmse_ridge","rmse_mean","mae_ridge","mae_mean","rel_improvement_vs_mean"],"status":"supported","caveat":"Difference is not statistically significant (DM p=0.59; block-bootstrap 95% CI [-0.158, 0.056])."},4 {"id":"C3","text":"All standardisation statistics and the target mean were recomputed from each origin's training window only (expanding).","results_keys":["normalisation_window","n_analysed"],"status":"supported","caveat":"Enforced in code by construction and an assertion on training target dates."}5]6