Harvey, David I.; Leybourne, Stephen J.; Taylor, A. M. … - In: Econometrics Journal 11 (2008) 3, pp. 409-442
In the context of regression-based (quarterly) seasonal unit root tests, we examine the impact of initial conditions (one for each quarter) of the process on test power. We investigate the behaviour of the well-known OLS detrended HEGY seasonal unit root tests together with their...