Personas

The most powerful tools are always simple in concept, but they often must be applied with some sophistication. That is certainly true of interaction design tools. Our most effective tool is profoundly simple: Develop a precise description of our user and what he wishes to accomplish. The sophistication comes from how we determine and use that precise description.

The most obvious approach to find the actual user and ask him doesn't work for a number of reasons, but the main one is that merely being the victim of a particular problem doesn't automatically bestow on one the power to see its solution. The actual user is still a valuable resource, and we devote considerable attention to him or her, but we never let the user directly affect the solution.

The actual method that works sounds trivial, but it is tremendously powerful and effective in every case: We make up pretend users and design for them. We call these pretend users personas,^[1] and they are the necessary foundation of good interaction design.

^[1] For all of you Latin scholars and typographers out there, you will be happy to know that the battle between "personas" and "personæ" rages hotly and daily at Cooper Interaction Design. Designers on the "personas" side argue that pronunciation is less ambiguous, gratuitous ligatures can be eliminated, and the word appears conventional and unthreatening to our clients. Designers on the "personæ" side argue that the pronunciation is easy once you hear it, the opportunity for a gratuitous ligature is like manna from heaven, and that our clients are bright enough to deal with arcane and obsolete phraseology. It sounds to me a lot like programmers arguing about algorithms, so, in this book, I'll stick to "personas."

Personas are not real people, but they represent them throughout the design process. They are hypothetical archetypes of actual users. Although they are imaginary, they are defined with significant rigor and precision. Actually, we don't so much "make up" our personas as discover them as a byproduct of the investigation process. We do, however, make up their names and personal details.

Personas are defined by their goals. Goals, of course, are defined by their personas. This may sound tautological, but it is not. Personas reveal themselves through our research and analysis in much the same way that the sequence of tectonic events reveal themselves to geologists through the study of sedimentary layers: The presence of a fossil defines a stratum, and a stratum defines the presence of a fossil. I'll talk a lot about goals in the next chapter, but we discover them in the same way we discover personas. We determine the relevant personas and their goals in a process of successive refinement during our initial investigation of the problem domain.

Typically, we start with a reasonable approximation and quickly converge on a believable population of personas. Although this iterative process is similar to the iterative process used by software engineers during the implementation process, it is significantly different in one major respect. Iterating the design and its premises is quick and easy because we are working in paper and words. Iterating the implementation is slow and difficult because it requires code.