The best reference check tip I’ve ever received is to leave voicemails for the references provided by your candidate. If you get a voicemail, which you almost always do, say: “Please call me back if this is an outstanding candidate for a job that requires learning.” If the candidate is outstanding, you’ll get a call back immediately. The reference might even apologize for missing your call. If you don’t hear back, leave one more message, but take note that you didn’t get an enthusiastic call back. If you still never hear from the person, take that as a very telling sign, and revel in the time you saved.