Here are my comments: your email would make for such a nice bug report,
if only you would add:
- a reproducible example of the fail in phtest()
- a reproducible example of your code, if it's yours, and also the
source of the code, if on the contrary you found it somewhere; because
as it is, you make it almost impossible to help you.
For more on this, please see the posting guide.
Anyway, in principle the Hausman test is correct. I've had code for this
lying around for ages, I'll try to add it to 'plm' one of these days;
but as in the end it is simply a joint restriction test, waldtest()
should work fine.