Chapter 6: Scenarios—Translating Goals into Design

In the two previous chapters, we described how to capture qualitative information about users. Through careful analysis of this information and synthesis of user models, we can get a clear picture of our users and their respective goals. We also explained how to prioritize which users are the most appropriate design targets. The missing piece to the puzzle, then, is the process of translating this knowledge into coherent design solutions that meet the needs of users while simultaneously addressing business needs and technical constraints.

This chapter describes a process for bridging the research-design gap. It employs personas as the main characters in set of techniques that rapidly arrive at design solutions in an iterative, repeatable, and testable fashion. This process has three major milestones: defining user requirements; using these requirements to in turn define the fundamental interaction framework for the product; and filling in the framework with ever-increasing amounts of design detail. The glue that holds the processes together is narrative : the use of personas to tell stories that point to design.

Narrative as a Design Tool

Narrative, or storytelling, is one of the oldest human activities. Much has been written about the power of narrative to communicate ideas. However, narrative can also, through its efficacy at engaging and stimulating creative visualization skills, serve as a powerful tool in generating and validating design ideas (Rheinfrank & Evenson, 1996). Because interaction design is first and foremost the design of behavior that occurs over time, a narrative structure, combined with the support of minimal visualization tools such as the whiteboard, is perfectly suited for envisioning and representing interaction concepts. Detailed refinement calls for more sophisticated visual and interactive tools, but the initial work of defining requirements and frameworks is best done fluidly and flexibly, with minimal reliance on technologies that will inevitably impede ideation.

Scenarios in design

Scenario is a term familiar to usability professionals, commonly used to describe a method of design problem solving by concretization (Carroll, 2001): making use of a specific story to both construct and illustrate design solutions. Scenarios are anchored in the concrete, but permit fluidity ; any member of the design team can modify them at will. As Carroll states in his book, Making Use :

Scenarios are paradoxically concrete but rough, tangible but flexible … they implicitly encourage ‘what-if?’ thinking among all parties. They permit the articulation of design possibilities without undermining innovation. … Scenarios compel attention to the use that will be made of the design product. They can describe situations at many levels of detail, for many different purposes, helping to coordinate various aspects of the design project.

Carroll's use of scenario-based design focuses on describing how users accomplish tasks (Carroll, 2001). It consists of an environmental setting and includes agents or actors that are abstracted stand-ins for users, with role-based names such as Accountant or Programmer.

Although Carroll certainly understands the power and importance of scenarios in the design process, the authors see two problems with scenarios as Carroll approaches them:

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  Carroll's scenarios are not concrete enough in their representation of the human actor. It is impossible to design appropriate behaviors for a system without understanding in specific detail the users of the system. Abstracted, role-oriented models are not sufficiently concrete to provide understanding or empathy with users.

• Carroll's scenarios jump too quickly to the elaboration of tasks without considering the user's goals and motivations that drive and filter these tasks. Although Carroll does briefly discuss goals, he refers only to goals of the scenario . These goals are somewhat circularly defined as the completion of specific tasks. Carroll's scenarios begin at the wrong level of detail: User goals need to be considered before user tasks can be identified and prioritized. Without addressing human goals, high-level product definition becomes difficult.

The authors believe that the missing ingredient in scenario-based design methods is the use of personas. A persona provides a sufficiently tangible representation of the user to act as a believable agent in the setting of a scenario. This enhances the designer's ability to empathize with user mental models and perspectives. At the same time, it permits an exploration of how user motivations inflect and prioritize tasks. Because personas model goals and not simply tasks, the scope of the problem that scenarios address can also be broadened to include product definition. They help answer the questions, "What should this product be ?" and "How should this product look and behave?" The authors address the issues surrounding task-based scenarios with the introduction of persona-based scenarios —scenarios incorporating the use of personas and goals.