Phone interviews are being used more and more as a tool to evaluate candidates before bringing them in for an interview. They save time and can help you determine whether you want to arrange for a face-to-face meeting. Before you call a prospective candidate, make sure you have a clear agenda of the items you want to cover. Organize your questions in advance so that your conversation will follow a natural and orderly process. It is courteous to schedule a phone interview rather than assume the candidate will have the time to talk whenever you call. Be prepared to ask him the same direct qualifying questions that you would ask in person.
If the candidate doesn't sound right on the phone, chances are he won't sound any better when you meet. If this is the case, you've saved yourself a lot of time. Go on to your next candidate.
Excerpted from Attracting & Rewarding Outstanding Employees