Seemingly Unrelated Time Series Equations and a Test for Homogeneity
似不相关时间序列方程与同质性检验
A multivariate structural time series model made up of unobserved components such as trends and seasonals is formulated. A homogeneous system, in which any linear combination of the observations follows the same time series process, is shown to correspond to a multivariate structural model in which the covariance matrices of the disturbances are proportional. A homogeneous model is considerably easier to estimate than the more general model and a score test of homogeneity…