validity of IPS test under unbalanced panel

[zscsere]

Hi all,
I was wondering about the interpretability/validity of the Im Pesaran Shin panel unit root test in case of an unbalanced panel. Now literature says the test only consideres balanced panels, and for unbalanced panels the Fischer type (ADF) tests should be used as proposed by Maddala and Wu.
However large scale simulations show that the IPS shows considerably better performance under ideal - balanced- circumstances.

Now my results are pretty similar for these tests, but I am unsure how much the IPS tests results are distorted /or interpretable in case of an unbalanced panel...
Thanks, Z