The vast majority of reference check calls should really be labeled validation calls. Once you have selected a winner, you have a few pleasant conversations with folks who will offer comforting, and hopefully enthusiastic, thumbs up on the candidate you want to hire. The dutiful among you will press references for some insights on perceived weaknesses or areas needing improvement.
But it is a rare reference call that will cause you to actually change your mind on a candidate. In fact, many busy general counsel will delegate reference checking to a recruiter (internal or external).