The last two times I have been asked to provide a telephone reference for someone, the person asking for the telephone reference began the conversation by informing me that they had decided to make X an offer (and, indeed, at least in one case X already been informed of this decision). I suspect that this not peculiar employer behavior but that there is a rationality to handling telephone references this way. But what is it?
One possibility, I suppose, is it makes the conversations a good deal shorter than they might be if a recommender felt s/he needed to lobby on the applicants’ behalf.

2 Comments
This sounds like a “reference check” required by HR and the person making the hiring decision is just going through the motions about it because they feel they already have enough information. So the callers are speeding the process of completing what they consider to be a pointless bureaucratic process. Or perhaps all they need to confirm is that the reference isn’t fake. It’s a different kind of interview when it is actually going to factor into the decision.
This is common in the UK. I think it’s partly because (a) References don’t mean much – if you can’t suggest someone that’s going to say something nice about you, then that’s pretty dreadful, and (b) they just want to know that the applicant hasn’t blatantly misrepresented themselves in some way.