Estimation of the memory parameter (d) is considered for models of nonstationary fractionally integrated time series with d gt; (1/2). It is shown that the log periodogram regression estimator of d is inconsistent when 1 lt; d lt; 2 and is consistent when (1/2) lt; d = 1. For d gt; 1, the...

A functional law for an I(1) sample data version of the continuous-path block bootstrap of Paparoditis and Politis (2001) is given. The results provide an alternative demonstration that continuous-path block bootstrap unit root tests are consistent under the null

While differencing transformations can eliminate nonstationarity, they typically reduce signal strength and correspondingly reduce rates of convergence in unit root autoregressions. The present paper shows that aggregating moment conditions that are formulated in differences provides an orderly...