I have unbalanced panel data and want to decide whether to compute (pooled) -logit-, -xtlogit,fe- or -xtlogit,re- (with Stata 14.2). The rho value of -xtlogit,re- is <0.05, so xtlogit,re is preferable compared to logit. Then, I have tested something similar for xtlogit,fe. After calculating -logit- and -xtlogit,fe-, I used -hausman-.
A value <0.05 would mean that I should prefer -xtlogit,fe- over the -logit- approach.

Code:
logit C_0 c.cube_root_A1 c.Sy2 Di3 c.Ex4
estimates store logit_C_0_1
xtlogit C_0 c.cube_root_A1 c.Sy2 Di3 c.Ex4, fe
estimates store xtlogit_fe_C_0_2
hausman  logit_C_0_1 xtlogit_fe_C_0_2
Array

Here we come to the question: -hausman- gives a negative value. I cannot use the functions "sigmamore" and "sigmaless", because Stata then gives me the following message: "Estimators do not save e(sigma) or e(rmse), sigma option not allowed". Using the command -suest-, as Stata suggests, makes no sense, because the command is not suitable for panel data. I cannot use the command -xtoverid- either, because the command does not work with (xt)logit. What other options do I have in such a situation?
In the Stata manual of the hausman test (page 9) it says: "[...]the χ2 statistic is actually negative. We might interpret this result as strong evidence that we cannot reject the null hypothesis." Can I apply this to my scenario? In that case (pooled) logit would be preferable to xtlogit,fe. In this case I would finally decide for the xtlogit,re approach. Is this procedure correct?