McFilter

The Second Law of Project Management

Quality isn't a variable.

I know that this is really a corollary to the first law, but I think it's important enough to put out on its own. It looks like it should be a variable, and that you can add features whilst maintaining the end date by reducing quality. But you can't (well, okay, you could, but this is so much of a "shouldn't" that it's easier to view it as a "can't" :-)

Quality is a constant. And it's value is "good enough" - any less and you're shipping bad software, any more and you're wasting time that would be better spent working on the next "good enough" product.