[sfamiliar]

no, we absolutely should not hold the developer responsible for the higher up questions -- the responsibility should fall on the shoulders of the person who made the decision. did the developer implement what he was asked? did he render solid feedback which was promptly ignored? if so, he bears no responsibility for the quality of the decision, only the quality of the implementation. if he made the decision, of course, that's a different matter. and in any case, the measurement of his 'productivity' is meaningless as a part of this metric.

comparing two programmers is possible. comparing a single programmer against a theoretical ideal is improbable. finding a remotely accurate formula for measuring developer productivity and yielding data that's actionable in the business space is really, really unlikely.