Michael Harmer (via Clarke Ching) has two posts that illustrate Jerry Weinberg’s idea that “quality is value to some person.”
When customer priorities aren’t explicit, developers will (naturally enough) fill in the blanks based on their own values.
Diana Larsen talks about creating that understanding up front in the project charter by defining management tests. Johanna Rothman uses Release Criteria to do the same thing.
However you choose to do it, understanding the value proposition for the customer will improve the ROI for the software you’re building.