Since a candidate cannot compare himself with people he doesn't know, all he can do is describe his incredible passion and desire and commitment and ... well, basically beg for the job. (Way too many interviewers ask the question and then sit back, arms folded, as if to say, "Go ahead. I'm listening. Try to convince me.")

And you learn nothing of substance.

Here's a better question: "What do you feel I need to know that we haven't discussed?" Or even "If you could get a do-over on one of my questions, how would you answer it now?"

Rarely do candidates come to the end of an interview feeling they've done their best. Maybe the conversation went in an unexpected direction. Maybe the interviewer focused on one aspect of their skills and totally ignored other key attributes. Or maybe candidates started the interview nervous and hesitant, and now wish they could go back and better describe their qualifications and experience.

Plus, think of it this way: Your goal as an interviewer is to learn as much as you possibly can about every candidate, so don't you want to give them the chance to ensure you do?

Just make sure to turn this part of the interview into a conversation, not a soliloquy. Don't just passively listen and then say, "Thanks. We'll be in touch." Ask follow-up questions. Ask for examples.