實證結果顯示，不同模型在上行與下行風險的預測上具異質性，Elastic Net在短期EL評估上表現較優，PCA與LSTM在中長期EL評估上均表現優異。而不同變數對通膨風險的影響在各分位間呈現分位數不對稱性，部分變數甚至在低分位與高分位方向相反，顯示傳統線性預測方法或許低估極端價格變動風險。本研究建議政策制定者應採用多模型架構與分量風險評估方法，不同觀察期採以不同模型分析，以強化通膨風險管理之全面性。 ;This study aims to establish an inflation risk assessment framework for Taiwan by integrating machine learning techniques with quantile regression to analyze the extreme fluctuation risks of the Consumer Price Index (CPI) annual growth rate across different forecast horizons. Using macroeconomic and financial data from Taiwan spanning January 2000 to October 2024, the study applies seven feature selection methods including LASSO, Elastic Net, Adaptive LASSO, PCA, Random Forest, XGBoost, and LSTM to extract key predictors from a high-dimensional dataset. These selected features are then incorporated into quantile regression models to estimate Inflation-at-Risk (IaR) at various quantiles. To better capture tail risk dynamics, the t-skew distribution is employed for smoothing, enabling the computation of Expected Shortfall (ES) and Expected Longrise (EL). Models with superior performance are identified, and the corresponding features are visualized using quantile coefficient plots. Finally, the study uses the gap between Q95 and Q5 as a measure to evaluate whether major policy adjustments help stabilize inflation risk.
Empirical results reveal heterogeneity in model performance regarding upward and downward risk prediction. Elastic Net performs better in short-term EL estimation, while PCA and LSTM outperform in medium to long-term EL forecasting. The impact of individual variables on inflation risk demonstrates nonlinearity and quantile-specific asymmetry, with some variables exhibiting opposite effects across low and high quantiles. These findings suggest that traditional linear forecasting models may underestimate extreme inflation risks. The study recommends that policymakers adopt a multi-model architecture and quantile-based risk assessment approach, applying different models across different forecast horizons to enhance the accuracy and robustness of inflation risk management.
