Asymptotic expansions are employed in a dynamic regression model with a unit root inorder to find approximations for the bias, the variance and for the mean squared error of theleast-squares estimator of all coefficients. It is found that in this particular context suchexpansions exist only when...

In the classical regression model with fixed regressors the statistic S2, i.e. the sum of squared residuals (SSR) divided by the number of degrees of freedom is an unbiased estimator of the variance of the disturbances. If the model is dynamic and contains lagged-dependent explanatory variables,...