how do you document the performance of a project after it is built?

buildings are an investment, regardless of the client. in todays competitive market, it would seem that there ought to be methods of quantifying the return on that investment, and this would be the most convincing sell... should building performance analysis after occupancy, comparisons to the clients goals be a part of design services? from a market value point of view, this would seem to make alot of sense...

green building technologies, energy efficiency, patterns of use, how a building meets the articulated goals of the client... and what about less quantifiable affects of design... would our profession be able to sell itself better if we expanded our job description to include measuring the performance of our product? would this be a way to foster our ongoing relationships with clients?

otherwise, are we assigning the success of the building to how many flashy magazines it is in, or how many awards it wins... is our profession then just a fashion industry? how do you measure the success of your buildings?