"Good" Advice

Is their such a thing as good or bad advice?

Isn't advice mainly subjective wisdom, or a method to solve a situation that someone has used that worked for them? It may or may not work for you...maybe that's where it becomes good or bad. This thought is brought to my mind by a story on the news this morning about one Dr. Richard Ferber. Okay, he has credentials. Does that make his advice good? He wrote a book on teaching babies to sleep, published in 1985, that is currently under scrutiny. Now, I have no babies, so I can offer no opinion on whether or not I like his advice. But, why is it just now (20 yrs later) becoming a contraversy, and can one really be mad at him for offering advice that may not have worked?

What exactly constitutes good advice?