Who Needs Facts, Andy?
I go for an expert in my own profession and I easily stand my ground facing the very best experts of my own industry at any time. I can calculate projects on the fly and yes when I see the fundamentals of a given project I have a feeling about how it will perform. Do I still calculate it? Sure thing. Because I had plenty of surprises when I did. Yes, someone who knows his stuff will have gut feelings but they will also be wrong more often than once. Actually, someone who is always right is not an expert. Thats a liar. And a fraud. Experts back their stuff up with data.