Sometimes, it can be plenty wrong!
The other day, my older daughter and I somehow got onto the subject of errors in official documents. I told her I had a doozy in my files.
The military has a database called the Defense Enrollment Eligibility Reporting System, known as DEERS. Several years ago, when my husband and I first got involved with the military health system, we went to get our data into the system. There was some wildly incorrect information already in the system about me.
First of all, I am old, but not this old -- it had my birth year as 1683. Please, people -- 1947 is long ago enough.
They actually had two databases being compared. The other one had my birth date correct. However, the DEERS database had my sex as "unknown" and the other database had me listed as a male.
Does someone need a pair of glasses? I am quite recognizably female. Besides, I've known a woman named Clifford, and read a historical document which mentioned a woman named Russell, but I have never heard of a male named Karen.
The DEERS data also had me as being on active duty at the time. No, by that time, it had been about 20 years since I had been on active duty.
The data got straightened out, and now the system has correct information about me.
Just remember, if you see an ancestor's information on a government report or document, do not assume automatically that it has been well-vetted! The information on it could be incorrect, and should be verified in other sources.