I was just watching a TV ad for 1-800-dentist, a dental marketer. In it a woman suggests to another that asking a friend for a recommendationn isn't a good idea. Says she, "1-800-dentist has been referring some dentists for 10 years, some even 15 ..." or words to that effect.
I feel so blessed to have had patients in my practice for 25 years and more. My favorite part ... the toddlers brought by their parents to see me for their first dental visit are now bringing their toddlers ... how cool, how very rewarding. Now THAT'S a patient referral.
So go ahead, ask a friend. They may not know hours of operation or where I went to school, but they know what they like, who they trust.
Btw, very early in my career I participated with a dental marketing service. I seem to remember that their "screening" process was little more than to check if I could pay their bill!