We apply the idea of using reversed time series to improve the power of Johansen tests. We suggest computationally simple variants of the trace and maximum eigenvalue statistics and establish their limit distributions. Both are shown, via simulation, to yield nontrivial power gains.

Unit root tests, seeking mean or trend reversion, are frequently applied to panel data. We show that more powerful variants of commonly applied tests are readily available. Moreover, power gains persist when the modifications are applied to bootstrap procedures that may be employed when...