Imagine if instead of trying to please everyone, you could design for three distinct people you knew very well. Wouldn't that make your job easier?
This is the power of personas, a technique for modeling users that we invented here at Cooper. As we interview and observe users in their natural habitats, we look for patterns of behavior and goals shared by multiple people. Each distinct behavior pattern becomes the basis for a persona: a description of an archetypal user.
Personas help everyone from programmers to executives understand users in a way no other tool can: at a gut level. Personas help guide design decisions, end those lengthy arguments about what users need, and get everyone to agree on what product you're building.
You don't need an enormous project to enjoy the benefits of personas. For short projects, personas may just be quick sketches based on limited data. For large initiatives with distributed teams, a well-researched and thoroughly documented set of personas can be an essential reference and communication tool.