Marc,
I'm going to have to ask if what you mean by functional analogs are those outputs that share similarities with the outputs of of other functions in the system, or in related systems. I think that is one of the things the ongoing assessment has to account for because that is how you get to a point of understanding. The only problem I see is the natural bias we all use when evaluating and assessing. You could even be seeing similar outputs but the purpose they serve could be different then the one you attribute to it and that could lead you to some bad assumptions. This is one of the reasons a good assessment is so difficult and may require a substantially sized element to do.

Could you send me an example or put one up here - I think it'd help us think more about it.
Best, Rob