Testing for seasonal unit roots in heterogeneous panels

This paper uses the approach of Im, Pesaran and Shin [Im, K.S., Pesaran, M.H., Shin, Y., 2003. Testing for unit roots in heterogeneous panels. Journal of Economics 115, 53–74.] to propose seasonal unit root tests for dynamic heterogeneous panels. The standardised t-bar and F-bar statistics are simply averages of the HEGY tests across groups. These statistics converge to standard normal variates