The chief value of this subject is preventing two people from being treated as one. If one namesake is reliable and the other weak, transferring the first person’s authentication to the second can change a chain’s grade. Combining the teacher of one with the pupil of another can even create a fictitious direct link.
Example: On encountering “Muḥammad ibn ʿUbayd,” locating the name in a biographical work is not enough. One must establish which individual fits the transmitters immediately before and after him.
The inquiry combines parallel chains, narrator generations, birth and death chronology, and explicit statements of critics. A proposed identification is credible only when it agrees with the wider transmission record.