The Heisenberg Uncertainty Principle--
Heisenberg says the more accurately we know where an electron is, the less accurately we can know what its velocity is. And vice versa. John Carroll talks about the Heisenberg Uncertainty Principle of Training: The more complete the training is, the less usable it is; the more usable it is, the less complete it is.

I believe the same goes for user assistance. The weight of being complete is not without its costs. For example, I recently read a user manual that explained the log in screen. By the way, this screen has two fields and one button. One field is labeled UserName and the other is labeled Password. The button is labeled Login.

It took a page with a screen shot to document how to log in. It turns out, after reading the manual, that I am supposed to put my UserName in the UserName field and my Password in the Password field. Then, according to the manual, I need to click on the button called Login.

There was some extra information: If I don't know my UserName and Password I should contact my System Administrator. And to get to the login page I need to type the IP address of the machine that is hosting this particular application in the URL address of my browser. Well, if I didn't know either of those things and went to the user assistance, I still don't know.

My question of the day is: If the UI is well designed and tells the user everything the user needs to know, do we need to document it at all?

What's the harm?
Why not document even the obvious? I can think of two reasons:

• It gets in the way. This user guide was 86 pages long. I can very quickly make it 85: Don't document the login screen. Let's assume that somewhere in that document is the one page the user needs. An 86-page document has 85 distractors (wrong or useless pages for that problem). An 85-page document has only 84 distractors. Not a big improvement, but hey, I was only on page two, who knows what I could do if I dug deeper.
• It fools us (the writers) into thinking we have documented the user's need. Maybe what this guide should have documented is how to read the IP address off of a machine. It was odd that it assumed a user would need help figuring out what to put in the Password field but would be adept at figuring out an IP address.