st: wald statistic value in xtgee

[Allison.Milner@student.griffith.edu.au]

Dear stata list,

I have a question about the Wald statistic in my xtgee analysis. There seems to be a big difference in the Wald value between models with and without one of my key IVs. 
For example, the wald statistic for one of my models is 1064.52	while the value for the other is 468.27
Basically this is the same problem that has been raised before on stata list (see below) but there appeared to be no response to this query.
Can anyone help?
Allison