<i>It biases you in a way which is completely unnecessary</i><p><i>If you aren't comfortable asking direct questions and need to go with a guy who got fired, you shouldn't be in a management position to begin with.</i><p>If you can't take in multiple opinions and judge the worth of them, then you <i>definitely</i> shouldn't be in <i>any</i> position where you have to interact with people or technology.  You also shouldn't be allowed on the Internet, lest you hurt yourself or others with horrible advice.<p>Your advice here is just so wrong that I can't even reasonably see a way for this to be a devil's advocate kind of position.  Ignoring available data before you know which data sources are accurate is foolish.  The guy resigned or got fired or whatever; OP only knows the non-technical hiring interviewer's side of the story (and that's filtered through CYA).  We don't know that the former IT guy is bitter in ways that would make him an unreliable source of information, you're just assuming he is.  We don't know that the hiring interviewer understood anything the former IT guys said, ever, about anything, including why he was dissatisfied; you're just assuming he does.<p>I don't care anything about the politics and crap that other folks seem to want to bring up.  A new IT guy <i>needs</i> to communicate with the old one in order to do a good job.  It's not optional.  The reason the old IT guy is available to talk is, I assume, because he believes in that professional courtesy even if he doesn't think much of his former employer.  I have never left an IT gig without at least a day of knowledge transfer, and any IT guy that would is not fit to do the job.<p>Have you ever worked in an IT position?  Arguing against talking to the old IT guy is like arguing against washing hands.  Best practices like these should not be mocked or made light of.