One of the presuppositions I make about ethical behaviour is that it always involves a conflict of values, and therefore judgments are constantly required to be made. It cannot be reduced to a set of simple rules--i.e., if you do this, then that's fine. Ethics are simply not like that.
The criteria I use in the first instance are the principles upon which the code is based--that is, both codes, and a set of principles upon which they're based. What I try to do is look at the material in front of me and say, “Does this threaten one of those principles in a serious way?” I can't know in advance just which of the principles are going to apply, just how it's going to threaten them. Each case will be quite different from another.
Those are the criteria I use, essentially--the principles.