Robert Martin points out that the important thing about Agile methods is that they produce real data, and data is what you need in order to really know where you are. 

Compare that to how most software projects are run. They begin with a date. Let's not kid ourselves, all projects start with a date -- probaly before they have requirements -- probably before they have a name. An endless stream of requirements follows. A project plan is put together, and then reformed and reformed until it meets the date. Then the project is launched, and from a management point of view it goes dark.

Managers ask "How's that project going?" The answer: "Pretty good." If you want a more detailed answer it will be something like this:

I'll let you read the rest at "Uncle Bob's corner".