The Effect of Existing Knowledge on Policy Analysis

Imagine that you are at a professional gathering, and you strike up a conversation with a colleague. The two of you end up in a lively discussion about the policy issues concerning development of a nearby wetland.

During the conversation, your colleague mentions that she, in fact, did some policy analysis associated with the project and says, "Well, I was a natural choice, given my degree in urban development."

As you head home, you ponder this. Obviously we all have existing knowledge, but how does, or how should, that affect the perspective one takes in the actual analysis of a policy matter? Do you believe that one's perspective on a policy matter should be driven by one's existing knowledge of the field under examination? What are the pros and cons of such an approach?