I believe the following: in evaluating someone's capacity for implementation in one level of abstraction, their understanding of the next level down is a good i

I believe the following: in evaluating someone's capacity for implementation in one level of abstraction, their understanding of the next level down is a good indicator (but neither necessary nor sufficient precondition) of their understanding of the whole of the system. I'm sorry for the grammatical awkwardness of the preceding sentence, edits welcome.