Figure 1.
Compact Modelling Framework for ARIMAX and LSTM Forecasting.
Figure 1.
Compact Modelling Framework for ARIMAX and LSTM Forecasting.
Figure 2.
Architecture Diagram of the LSTM Cell.
Figure 2.
Architecture Diagram of the LSTM Cell.
Figure 3.
Time Series Plot of Quarterly Unemployment Rate.
Figure 3.
Time Series Plot of Quarterly Unemployment Rate.
Figure 4.
Time Series Decomposition Plot of Unemployment Rate.
Figure 4.
Time Series Decomposition Plot of Unemployment Rate.
Figure 5.
ACF and PACF Plots of the Unemployment Time Series Data.
Figure 5.
ACF and PACF Plots of the Unemployment Time Series Data.
Figure 6.
Structural Break Analysis Plot.
Figure 6.
Structural Break Analysis Plot.
Figure 7.
Rolling Plot of Standard Deviation.
Figure 7.
Rolling Plot of Standard Deviation.
Figure 8.
Time Series Plot of Unemployment Rate with COVID Highlight.
Figure 8.
Time Series Plot of Unemployment Rate with COVID Highlight.
Figure 9.
Unemployment Covariates Plot.
Figure 9.
Unemployment Covariates Plot.
Figure 10.
Correlation Matrix of Unemployment Covariates.
Figure 10.
Correlation Matrix of Unemployment Covariates.
Figure 11.
Time Series, ACF, and Histogram with Density Curve Plots of the ARIMAX Residuals.
Figure 11.
Time Series, ACF, and Histogram with Density Curve Plots of the ARIMAX Residuals.
Figure 12.
Normal Q–Q Plot of the ARIMAX Residuals.
Figure 12.
Normal Q–Q Plot of the ARIMAX Residuals.
Figure 13.
ARIMAX In–Sample Forecast of Unemployment Rate.
Figure 13.
ARIMAX In–Sample Forecast of Unemployment Rate.
Figure 14.
ARIMAX Out–of–Sample Forecasts vs Test (Actual) data.
Figure 14.
ARIMAX Out–of–Sample Forecasts vs Test (Actual) data.
Figure 15.
Training vs Validation Loss.
Figure 15.
Training vs Validation Loss.
Figure 16.
Time Series, ACF & PACF, and Histogram with Density Curve Plots of LSTM Residuals.
Figure 16.
Time Series, ACF & PACF, and Histogram with Density Curve Plots of LSTM Residuals.
Figure 17.
Normal Q–Q Plotof LSTM Residuals.
Figure 17.
Normal Q–Q Plotof LSTM Residuals.
Figure 18.
LSTM Out–of–Sample Forecast of Unemployment Rate vs Test (Actual) data.
Figure 18.
LSTM Out–of–Sample Forecast of Unemployment Rate vs Test (Actual) data.
Figure 19.
Rolling RMSE Plot of LSTM Residuals.
Figure 19.
Rolling RMSE Plot of LSTM Residuals.
Figure 20.
Out–of–Sample Forecast Comparison Plot: ARIMAX vs LSTM.
Figure 20.
Out–of–Sample Forecast Comparison Plot: ARIMAX vs LSTM.
Figure 21.
Murphy Diagram: ARIMAX vs LSTM Forecasts.
Figure 21.
Murphy Diagram: ARIMAX vs LSTM Forecasts.
Figure 22.
Forecast Error Distribution: Boxplot of ARIMAX vs LSTM errors.
Figure 22.
Forecast Error Distribution: Boxplot of ARIMAX vs LSTM errors.
Figure 23.
Accumulated forecast deviations over time.
Figure 23.
Accumulated forecast deviations over time.
Figure 24.
Forecast Error Histogram Plot: Distribution of ARIMAX vs LSTM forecast errors.
Figure 24.
Forecast Error Histogram Plot: Distribution of ARIMAX vs LSTM forecast errors.
Figure 25.
Forecast vs Actual Values for ARIMAX and LSTM Models.
Figure 25.
Forecast vs Actual Values for ARIMAX and LSTM Models.
Figure 26.
Heatmap of Forecast Errors for ARIMAX and LSTM Models.
Figure 26.
Heatmap of Forecast Errors for ARIMAX and LSTM Models.
Table 1.
LSTM Hyperparameter Grid for Model Tuning.
Table 1.
LSTM Hyperparameter Grid for Model Tuning.
| Hyperparameter |
Values Tested |
| Number of Units |
50, 100 |
| Dropout Rate |
0.2, 0.3 |
| Batch Size |
8, 16 |
| Epochs |
100 |
| Loss Function |
Huber Loss |
| Optimizer |
Adam (learning rate = 0.001) |
| Lag Length |
8 |
| Early Stopping |
Patience = 10 |
| Validation Split |
20% |
Table 2.
Summary Statistics of Unemployment Rate (%).
Table 2.
Summary Statistics of Unemployment Rate (%).
| Statistic |
Min |
1st Qu. |
Median |
Mean |
3rd Qu. |
Max |
SD |
Skew |
Kurt |
| Value |
21.50 |
24.90 |
26.70 |
27.74 |
31.90 |
35.30 |
3.80 |
0.49 |
-1.13 |
Table 3.
Stationarity Test Results for Unemployment Rate Time Series.
Table 3.
Stationarity Test Results for Unemployment Rate Time Series.
| Test |
Test Statistic |
Lag |
p-value |
Conclusion |
| ADF |
-2.3508 |
4 |
0.4325 |
Non-stationary |
| KPSS |
1.653 |
3 |
<0.01 |
Non-stationary |
Table 4.
Diagnostic Test Results for Unemployment Rate Time Series
Table 4.
Diagnostic Test Results for Unemployment Rate Time Series
| Test |
Test Statistic |
Lag |
p-value |
Conclusion |
| Ljung–Box |
497.79 |
20 |
<0.001 |
Autocorrelation present |
| ARCH LM |
51.153 |
12 |
<0.001 |
ARCH effects present |
Table 5.
Variance Inflation Factor (VIF) Results for Covariates.
Table 5.
Variance Inflation Factor (VIF) Results for Covariates.
| Variable |
VIF |
| Discouraged |
1.296 |
| NEA |
1.296 |
Table 6.
Correlation Significance (p-values) Among Covariates.
Table 6.
Correlation Significance (p-values) Among Covariates.
| |
Discouraged |
ONEA |
| Discouraged |
0.0000 |
0.0000 |
| NEA |
0.0000 |
0.0000 |
Table 7.
Granger Causality Test Results (Lag Order = 2).
Table 7.
Granger Causality Test Results (Lag Order = 2).
| Covariate |
F-Statistic |
p-value |
Conclusion |
| Discouraged |
0.415 |
0.6622 |
No Granger causality |
| NEA |
22.857 |
<0.001 |
Granger causality present |
Table 8.
Stationarity Test Results for Covariates.
Table 8.
Stationarity Test Results for Covariates.
| Variable |
Test |
Test Statistic |
Lag |
p-value |
| Discouraged |
ADF |
-4.6073 |
4 |
<0.01 |
| Discouraged |
KPSS |
1.6066 |
3 |
<0.01 |
| NEA |
ADF |
-2.7590 |
4 |
0.2664 |
| NEA |
KPSS |
0.8977 |
3 |
<0.01 |
Table 9.
Stationarity Tests for Differenced NEA Series.
Table 9.
Stationarity Tests for Differenced NEA Series.
| Test |
Test Statistic |
Lag |
p-value |
| ADF |
-4.9209 |
4 |
|
| KPSS |
0.0430 |
3 |
|
Table 10.
Estimated ARIMAX Model Coefficients.
Table 10.
Estimated ARIMAX Model Coefficients.
| Variable |
Estimate |
Std. Error |
t-value |
p-value |
| SMA(1) |
0.1744 |
0.1319 |
1.3215 |
0.1863 |
| SMA(2) |
0.5118 |
0.1875 |
2.7293 |
0.0063*** |
|
Discouraged |
0.0010 |
0.0008 |
1.1849 |
0.2361 |
|
NEA |
0.0008 |
0.0002 |
4.8105 |
0.0000*** |
|
Note: *** p<0.01, ** p<0.05, * p<0.1 |
Table 11.
ARIMAX Model Fit and Diagnostic Statistics.
Table 11.
ARIMAX Model Fit and Diagnostic Statistics.
| Statistic |
Value |
| Model |
ARIMA(0,1,0)(0,0,2)[4] |
|
1.309 |
| Log-likelihood |
-84.62 |
| AIC |
179.23 |
| AICc |
180.46 |
| BIC |
189.27 |
| ME |
0.1565 |
| RMSE |
1.0920 |
| MAE |
0.6467 |
| MAPE |
2.4002 |
| MASE |
0.4867 |
| ACF1 |
-0.0137 |
Table 12.
Shapiro-Wilk Normality Test for ARIMAX Residuals.
Table 12.
Shapiro-Wilk Normality Test for ARIMAX Residuals.
| Test |
Statistic (W) |
p-value |
| Shapiro-Wilk |
0.7648 |
|
Table 13.
Autocorrelation and Heteroskedasticity Test Results on the ARIMAX Residuals.
Table 13.
Autocorrelation and Heteroskedasticity Test Results on the ARIMAX Residuals.
| Test |
Statistic |
Lag |
p-value |
| Box-Ljung |
6.8146 |
20 |
0.9973 |
| ARCH LM |
12.009 |
12 |
0.445 |
Table 14.
Out-of-Sample ARIMAX Forecasts with 95% Prediction Intervals.
Table 14.
Out-of-Sample ARIMAX Forecasts with 95% Prediction Intervals.
| Period |
Forecast |
Lower (95%) |
Upper (95%) |
| 2022 Q1 |
33.352 |
31.109 |
35.595 |
| 2022 Q2 |
33.798 |
30.626 |
36.969 |
| 2022 Q3 |
36.686 |
32.802 |
40.571 |
| 2022 Q4 |
37.021 |
32.535 |
41.506 |
| 2023 Q1 |
37.484 |
32.283 |
42.686 |
| 2023 Q2 |
37.525 |
31.695 |
43.355 |
| 2023 Q3 |
38.045 |
31.648 |
44.443 |
| 2023 Q4 |
37.688 |
30.770 |
44.607 |
| 2024 Q1 |
37.945 |
30.060 |
45.829 |
| 2024 Q2 |
38.064 |
29.320 |
46.809 |
| 2024 Q3 |
37.896 |
28.369 |
47.422 |
| 2024 Q4 |
38.021 |
27.771 |
48.271 |
| 2025 Q1 |
37.841 |
26.915 |
48.766 |
| 2025 Q2 |
38.070 |
26.509 |
49.631 |
Table 15.
Out-of-sample Forecast Accuracy Measures for ARIMAX Model.
Table 15.
Out-of-sample Forecast Accuracy Measures for ARIMAX Model.
| Model |
RMSE |
MAE |
MAPE |
| ARIMAX |
4.8171 |
4.5094 |
0.1388 |
Table 16.
Diagnostic Tests for LSTM Residuals.
Table 16.
Diagnostic Tests for LSTM Residuals.
| Test |
Statistic |
df |
p-value |
| Ljung-Box |
9.8963 |
10 |
0.4496 |
| ARCH LM |
2.0000 |
12 |
0.9994 |
Table 17.
Out-of-Sample LSTM Forecasts with 95% Prediction Intervals.
Table 17.
Out-of-Sample LSTM Forecasts with 95% Prediction Intervals.
| Period |
Forecast |
Lower (95%) |
Upper (95%) |
| 2022 Q1 |
32.975 |
31.180 |
34.770 |
| 2022 Q2 |
31.919 |
30.124 |
33.714 |
| 2022 Q3 |
32.355 |
30.560 |
34.150 |
| 2022 Q4 |
32.373 |
30.577 |
34.168 |
| 2023 Q1 |
32.194 |
30.399 |
33.990 |
| 2023 Q2 |
32.870 |
31.074 |
34.665 |
| 2023 Q3 |
33.210 |
31.415 |
35.005 |
| 2023 Q4 |
33.184 |
31.388 |
34.979 |
| 2024 Q1 |
31.919 |
30.124 |
33.714 |
| 2024 Q2 |
32.619 |
30.823 |
34.414 |
| 2024 Q3 |
32.373 |
30.577 |
34.168 |
| 2024 Q4 |
32.166 |
30.371 |
33.962 |
| 2025 Q1 |
32.870 |
31.074 |
34.665 |
| 2025 Q2 |
32.963 |
31.168 |
34.758 |
Table 18.
Out-of-Sample Forecast Accuracy Measures for LSTM Model.
Table 18.
Out-of-Sample Forecast Accuracy Measures for LSTM Model.
| Model |
RMSE |
MAE |
MAPE |
| LSTM |
0.8195 |
0.7319 |
0.0224 |
Table 19.
Out-of-Sample Forecast Performance Comparison.
Table 19.
Out-of-Sample Forecast Performance Comparison.
| Model |
RMSE |
MAE |
MAPE |
| ARIMAX |
4.8171 |
4.5094 |
0.1388 |
| LSTM |
1.1809 |
0.9469 |
0.0293 |
Table 20.
Diebold–Mariano (DM) Test for Forecast Accuracy Comparison.
Table 20.
Diebold–Mariano (DM) Test for Forecast Accuracy Comparison.
| Statistic |
p-value |
Test |
| 7.4663 |
0.0000 |
DM |
Table 21.
Model Confidence Set (MCS) Results at 95% Confidence Level.
Table 21.
Model Confidence Set (MCS) Results at 95% Confidence Level.
| Model |
Average Loss |
p-value () |
MCS p-value |
| ARIMAX |
23.2040 |
0.0000 |
0.0000 |
| LSTM |
1.3945 |
1.0000 |
1.0000 |
Table 22.
Bootstrap Confidence Intervals for RMSE.
Table 22.
Bootstrap Confidence Intervals for RMSE.
| Model |
Lower Bound |
Upper Bound |
| ARIMAX |
4.1314 |
5.3874 |
| LSTM |
0.8047 |
1.5066 |
Table 23.
Prediction Interval Coverage at 95% Confidence Level.
Table 23.
Prediction Interval Coverage at 95% Confidence Level.
| Model |
Coverage (%) |
| ARIMAX |
92.86 |
| LSTM |
78.57 |
Table 24.
Non-parametric Comparison of Forecast Errors: ARIMAX vs LSTM.
Table 24.
Non-parametric Comparison of Forecast Errors: ARIMAX vs LSTM.
| Test |
Statistic |
p-value |
Median / Shift |
95% CI |
| Sign Test |
|
0.0018 |
|
|
| Wilcoxon Signed-Rank Test |
|
0.0002 |
– |
– |