st: xtoverid following xtreg returning an error

[Jason Park <loooooo.j8311@gmail.com>]

Hi all,

I got some wierd error when I used xtreg, re followed by xtoverid.
The error message reads:
4b:  operator invalid
r(198);

The reason to use xtoverid in the first place is to get around the
problem of a negative Chi-sq statistic from Hausman test upon
performing:
xtreg, re
estimate store, random
xtreg, fe
estimate store, fixed
hausman fe re

Given that Hausman test doesn't always gurantee a positive stat, some
argue such a negative statistic is qualitatively identical to a small
stat, hence supporting re, but I don't know if that's really how I
should report in an academic publication.
Having tried the instruction on this webpage:
http://kb.iu.edu/data/bcmq.html, I'm very sure xtoverid is compatible with
xtreg, but it's just that this doesn't work for my dataset.

Could anyone lend some help?

Best, J
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/