Dear researchers,

I am using the following code
Code:
 xtreg GG SIZE LEV ROA i.year, fe cluster (COMPANY)
I have applied the following command to see if their is a serial correlation or not:
Code:
predict resid, resid
runtest resid
And, the Stata showed me the following message:
Code:
 resid has internal missing observations
r(498)
Is their any suggestion on how to fix it??


Thank you very much in advance.