Scenarios

As the design work becomes more detailed, scenarios become more and more effective. We play our personas through these scenarios, like actors reading a script, to test the validity of our design and our assumptions. Not surprisingly, our scenario process has been described as very like method acting, in which the actor must inhabit the character, knowing what he knows and feeling his feelings. We try to think the way our persona thinks. We forget our own education, ability, training, and tools, and imagine ourselves as having his background instead. Because we are designers and not actors, this can be difficult without some specific context and detail, so scenarios are very useful. Knowing that Betsy is trying to create a Web site for an insurance company, for example, we can more easily inhabit her character. This is not as strange as it might sound. After all, programmers inhabit the personalities of their computers. It is common for a programmer to describe the actions of the computer in the first person to say, "I access the database, then I store the records in my cache." Although she says "I," she is not doing a thing: The computer is doing the work, but by assuming the character of the computer, she can more easily sympathize with the system's needs as she codes.

Scenarios are constructed from the information gathered during our initial investigation phase. Typically, in both interviews and direct observation of users, we learn a lot about their tasks. Goals are stable and permanent, but tasks are fluid, changeable, and often unnecessary in computerized systems. As we develop scenarios, we need to seek out and eliminate tasks whose only justification is historical.

Effective scenarios need to be complete in breadth more than in depth. In other words, it is more important that the scenario is described from start to finish than that it cover each step in exhaustive detail.

It is important to develop only those scenarios that will further the design effort and not to get lost in edge cases. We develop only two types of scenarios, although there might be more than one of each kind. The scenario types are daily use and necessary use.