Best evidence is evidence that establishes a person's DB regardless of other evidence which may exist. Therefore, in a material discrepancy case when best evidence is submitted by a claimant for whom there is no NUMIDENT or other SSA record of age, another record of age need not be obtained. This is an exception to the rule that at least two documents must be obtained when a DB determination is based on other than preferred evidence.

When a second document is not obtained, document the file to show that best evidence has in fact been submitted. Follow GN 00302.170 to determine the type and amount of documentation needed.