It's a great thing in theory, and no doubt has it's place. But in over a half dozen attempts at various contract assignments in as many years I've had the following problems.

• Why can't we just use that? What do you mean we have to start all over?
• It didn't take you that long to do it the first time! Why now?(see above)
• It didn't look like that in the prototype. (when prototyping & implementation tools are different...)
• We've been thinking, and that was really great, but now that you're doing it for real we want something different.

What's never happened:

• Great! This is a really handy way of seeing how this is gonna work.
• No no, I understand, this is just a virtual mock-up.

Now I ain't sayin' it's impossible. And I could have just drawn bad lots. But strike me down if I've ever seen it work. Technically it's a wonderful approach (just like my new favorite practice of writing the test tools from the "spec" before even TOUCHING the code body.) But in practice, I'm cynical at best. But then again, I'm a New Yorker.

- V