Reference check
A reference check is a conversation with a candidate's former managers or colleagues to verify their track record and working style before an offer. It is most useful for confirming how someone operates, and least useful when the references are hand-picked by the candidate.
Because candidates choose their own referees, a reference check rarely surfaces hard negatives and should not carry an offer on its own.
Treat it as confirmation, and as guidance on how to manage the person well once hired, rather than as a primary screen. The real evaluation work belongs to the structured interview and the test assignment.