1[2 {"id":"C1","text":"At h=1 the ARIMA(2,1,0) model does not beat the naive forecast: its RMSE and MAE are both slightly higher (relative RMSE improvement about -2.3%).","results_keys":["rmse_naive_h1","rmse_model_h1","mae_naive_h1","mae_model_h1","rel_improvement_rmse_h1"],"status":"supported","caveat":"35 evaluated pairs, final-vintage data, single 3-year window."},3 {"id":"C2","text":"At h=3 the model does not beat the naive forecast: its RMSE and MAE are marginally higher (relative RMSE improvement about -0.5%).","results_keys":["rmse_naive_h3","rmse_model_h3","mae_naive_h3","mae_model_h3","rel_improvement_rmse_h3"],"status":"supported","caveat":"Overlapping 3-month errors; small sample."},4 {"id":"C3","text":"The squared-loss difference is statistically detectable at h=1 (DM p about 0.02) but not at h=3 (p about 0.34).","results_keys":["dm_stat_h1","dm_pvalue_h1","dm_stat_h3","dm_pvalue_h3"],"status":"supported","caveat":"DM test ignores that the model nests the random walk; small sample; treat as approximate."},5 {"id":"C4","text":"Each horizon has 35 of 36 pairs evaluated because the 2025-10-01 observation is missing.","results_keys":["n_evaluated_h1","n_evaluated_h3","n_origins","data_issues"],"status":"supported","caveat":""},6 {"id":"C5","text":"The last training window contains 941 observations after 1 missing value and 3 post-origin months are excluded from the 945 input rows.","results_keys":["n_analysed","n_input_rows"],"status":"supported","caveat":""}7]8