The Devil is in the details
If you believe what Bill Buxton has been advocating, and for the record I do, we all need to be using state diagrams in conjunction with our static rapid prototypes and storyboards. He states the most important parts of any design, whether software or hardware, are the transitions. What happens when your UI changes from one state to the next? Is it smooth or abrupt? Do you give the user enough feedback so they know what is going on? More importantly, what does your user perceive of this? Between every one of your static pages there was some event or series of events that merge together to form a transition. The details of what happens in transitions can make or break your design.
Apparently Microsoft did not Get the Memo
Jeff Atwood discusses a real world example in his post about the new Microsoft Vista copy feature. In a nut shell, the new Vista copy feature has been completely overhauled. It is faster, less error prone, and more efficient. Everyone should be ecstatic, right? Nope, a quick Google search indicates most do not think the file copy is faster. To the average person the new file copy feature appears to be slower. You see, in Windows XP the progress bar indicates complete and disappears before the file has actually completed copying. In Vista the progress bar stays until completion, providing an accurate, real-time status for the user. There are also very valid technical reasons for this (read this post to learn more). On paper, everything makes sense and the end result should have been better for the end user. But if you were to compare how long the progress bar is displayed in XP to Vista, Vista appears to be slower. Paper says better, reality says worse. The bottom line, a better, much improved feature is now one more piece to the argument that Vista is a slow resource hog.
The Vista example is a great one because as much flak as Vista gets, it actually is a pretty good OS, and it is in fact better than XP. But to the end user it appears slow and bloated. I don’t know any of the programmers or designers that worked on Vista, but I am willing to bet that they did not do the work up front to define and test all of the transitions that occur.Imagine if they had used a couple of state diagrams when designing the copy feature. They could have tested display times, how fast the progress bar moved across, how long it should have been, etc. Before a single line of code had been written they could have defined exactly how the feature should have worked. And let’s all be honest with one another, code is a lot harder to change than a simple diagram.