SELF-WEIGHTED ESTIMATION FOR LOCAL UNIT ROOT REGRESSIONS WITH APPLICATIONS
局部单位根回归的自加权估计及应用
A new self-weighted (SW) least squares (LS) estimation approach is developed for local unit root (LUR) autoregression with conditionally heteroskedastic innovations. Asymptotically controlled trimming of the most extreme observations in LS regression is shown to lead to mixed Gaussian limit theory and studentization produces standard normality free of the unknown LUR parameter. The estimator is super consistent with a convergence rate slightly below the O P ( n ) $O_P(n)$ upp…