Research into narrator identity must not rely exclusively on similarity or difference in spelling. The same expression can name different people, while two different expressions may refer to one person.
First indication: the teachers and pupils and whether transmission was possible.
Second: chronology and locality, establishing genuine overlap.
Third: additional identifiers, including kunya, title, clientage and genealogy.
Fourth: comparison of independent biographical sources and full chains.
These indications collectively determine confidence in identification. If the evidence is inconclusive, the remaining ambiguity should be acknowledged.