Personas and Goal-Directed Design: An Interview with Kim Goodwin
http://www.uie.com/articles/goodwin_interview/

Klee, Matthew
User Interface Engineering
2001

Abstract:

We use personas because they are powerful design, measurement, and communication tools. We use them in design to help us avoid the elastic user problem--where "the user" is a total novice one minute and a technophile the next--as well as self-referential design, because designers are seldom representative of a product's target audience. Personas also help cut through assumptions that certain tasks are necessary; if a task doesn't directly help accomplish a goal, we can try to eliminate it.