Enterprise Architecture: Earning our keep

Does anyone ever ask you to justify what you do?  I've worked in most roles in technical development and management.  Only in Enterprise Architecture do I get that question.  So I'm posing an open question to the EA community: how do you demonstrate value?

There's no question what a tester is for.  You can point to the consequences of poor testing by demonstrating a large number of defects making it to production.  Poor development practices produce a more complex answer, but the system quality attributes provide measurements for the software development profession.

So what is the measurement for EA?  What is the proof that we are needed?

What fact or problem or number can you point to that says "this company needs EA?" 

Getting folks organized around the concept of Enterprise Architecture is tough.  You have to show that there is a problem that the company is unable to solve without EA.

The thing is: the problems that EA can solve are really not that many.  Yes, we can drive strategic alignment, but we aren't the only ones that do that.  In fact, if IT does align with the business, there is no way that EA gets credit for it.  Making IT align with the business usually means making people very angry.  The folks will will benefit are NOT the same as the folks who are hurt.  If IT doesn't align with the business, then it's business as usual.  Either way, EA looks like a waste of money.

We can "model the enterprise" until the cows come home, but if we do that, we need to answer the question "Why would anyone want a model of the enterprise?"  I work in the Seattle area, where the Boeing company builds most of their commercial airliners.  When Boeing creates a model of a new airplane, it is for a purpose... often they want to test the model, but sometimes it helps to create a visual representation of a new design for other purposes as well.

So it comes back to the purpose.  What is the purpose for EA in your company? How do you answer the question: "This is the measurement that we are paid to improve?"

If we have a clear measurable... a clear consequence that occurs when we are NOT here... then EA gets a lot easier to maintain.

I have ideas for what I think it should be, but I'd be interested in what you have to say.  How do you go about demonstrating that EA is a good investment?