An 1881 affidavit in a War of 1812 pension case mentioned three children of the veteran and his wife. The youngest of those three was the one making out the affidavit and she referenced the dates of birth for her two older siblings.
That was necessary to backtrack into a time frame for her parents’ marriage. Information on the younger children was not necessary to establish that marriage date–so they aren’t mentioned.
The genealogist needs those names.
The pension official did not.
Always keep in mind the original purpose of any document and analyze it in that context.
Not your own.
The document may have been complete and accurate given the situation in which it was created. A lot of us don’t do more work than we need to. Our ancestors were no different.
This affidavit was analyzed in more detail in a recent issue of Casefile Clues.