Thomas Coleman, CUA

"While the first work product of programmers is a tentative solution to the user’s needs, the first work product of interaction designers is a narrative restatement of the problem being addressed.

These narrative descriptions of users and their goals are compelling stories primarily composed for managers and marketers. When these non-technical people read them, they can clearly see if their product and market ideas are viable.
 
An executive or marketer may not be able to look at a screen and judge whether what he sees is correct or not, but he will be able to read stories about real users and make that judgment.
 
This can prevent the entire team from heading down a blind alley."

  --Alan Cooper