That's a very good question.
My perspective as a health economist is that I help people see how much extra they're going to have to pay and what they're going to get, so I describe this as positive analysis. It's seeing, basically in Consumer Reports style, that if we have a new drug, how much longer the patient is going to live with it and how much more it will cost. There's a second part called “normative”, wherein you actually tell people what they should do.
I feel that my role should be to give decision-makers information they can understand. If they think this is good value for money, they can make the funding decision. If they think “no, it's not”, that's okay. My role is to get them the information to inform the decision.