Reliabilty

Reliability of information on records

Think about who gave the information. Did they know or are they guessing?

It was (and is) an offence to give wrong information.  Misinformation was usually given in good faith.

Information on parents' names

On birth certificates - should be 100% accurate
One of the parents is giving the information so unless they are deliberately trying to deceive, it should be accurate.

An illegitimate grandchild may be brought up as a child, a "late" baby.  The birth certificate should reveal the truth.

On marriage certificates the information is given by the bride and groom, so should be 100% accurate unless they don't actually know the truth or have been given misinformation on their parentage.

On death certificates especially of an old person whose grandchild is giving the information, it may well be a best guess.