1. Introduction
2. Overview of the Conventional Productive Regression
3. Model Spectication
3-1 Comparison with a Conventional Predictive Regression
3-2 Why Does the Predictive System Produce Better Forecasting Performance?
4. Estimation Procedure
4-1 A State-Space Representation
4-2 Forecasting Evaluation
5. Empirical Application
5-1 Data
5-2 The Preictability of the Export Growth Rate
5-3 The Predictability of the Import Growth Rate