The interview process, or some sort of skills assessment process, is still necessary even after the referral. Otherwise, you run the risk of hiring someone akin

The interview process, or some sort of skills assessment process, is still necessary even after the referral. Otherwise, you run the risk of hiring someone akin to the boss' nephew who claims web programming skills, but has never been in the same room as someone who has those skills. Relying on friends and colleagues for advice on who to hire is good, but it can turn bad if that is the only data point you rely on.