I find it interesting that you presume the hit rate on bringing people in based on resumes would be very low. I can tell a good engineer from a bad one, pretty well, using resumes.

Phone screens, however are a waste of time. It is difficult to establish rapport with someone over the phone, for both parties, and I've seen some people actually ask programming questions over the phone.

One very good engineer I hired, back before I was running my own show, did terrible on the phone screen.

I brought her in, though, because I saw something in the resume. She's asian and had a real problem talking on the phone, but eventually got the job and was great.

You are making a decision with an enormous impact. Therefore, it is critical that you do it based on a truthful assessment of the candidate-- not ideological prejudice.