Three kinds of evidence are foundational. Generation places a narrator in time; teachers and pupils establish possible direct transmission links; and locality and travel indicate where an encounter could have occurred. Together they provide a firmer basis than the name alone.
Example: One namesake is known in Kufa and another in Mecca. A teacher in the chain is associated only with Kufa, making the Kufan candidate more plausible, though geography alone is not decisive. A parallel chain that explicitly identifies the pupil can strengthen the conclusion.
Evidence differs in weight: chronological compatibility establishes possibility, while an explicit identification in another chain may offer more direct confirmation.