There's a mischievous response to the question "Can you measure the effectiveness of my advertising?", which will sometimes lead to a very straight answer and occasionally cause a client or planner to tie themselves completely in knots.
It's "Sure, what was it supposed to change?"
It's most fun to ask a room full of people and find out that they all think the campaign was supposed to do different things. The finance guy is talking about selling product, the head of marketing is talking about building the brand and somebody else chips in with 'making a noise' or possibly 'maintaining share of voice'.
Building the brand is a difficult one to define because it means so many things to different people. Do we mean awareness? Consideration? Preference? If you can't define the word brand, then setting it as a campaign objective - even implicitly - is fraught with problems.
In the Era of Marketing AccountabilityTM, shouldn't everybody be clear on what their marketing budget is designed to achieve?