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2.2. SCENARIOS
With new-generation products, scenarios are a key device used to bridge the Exploratory, Refinement and Analysis, and Formal Design Stages. Scenario techniques have been applied in many different ways, and indeed the term scenario itself has many interpretations (see Caroll, 1995). This chapter will focus on user interaction scenarios, which are narrative descriptions of what people do and experience as they try to make use of a product and its applications.
One of the characteristics of new-generation products is that potential users can have difficulty understanding the proposed new product or articulating what they would want the new product to do. Unlike lists of features, scenarios provide potential users with a feel for how the product would perform in a specific situation or context. Scenarios include a concrete description of the users activities, focusing on a particular instance of use. Scenarios are a user-centric perspective on task/application interaction: what happens, how it happens, and why it happens. Particularly with consumer products, the scenario should encompass and present a totally integrated package for evaluation by the user. This package can include the interface, the physical product, the context of use, and the various users.
The user-centric perspective is important in that the users model and the designers model are usually different. Spool (1996) uses the example of Walt Disney Worlds Haunted House: The designers decide what ghosts, lighting, screams and general spookiness the guests would experience... If the guests come out of the ride thinking that the 180 watt surround sound speaker system really added to the ride, then the ride itself has failed.
User interaction scenarios can be communicated in a variety of forms, for example, a narrated story (text-based narrative), a picture-based story (using story-boards), a scripted computer-based simulation, a simple scripted play with live actors (actors can be members of the design team), or a video with professional actors. Caroll (1995) provides a good overview of the advantages and disadvantages associated with the various scenario presentation techniques.
2.2.1. Role of Scenarios in the Exploratory Stage
In the Exploratory Stage, scenarios are used to clarify the use of a new-generation product, not only for the end user, but also for the design team. They are an effective method of brainstorming to create new product concepts and a shared vision in a multidisciplinary team. This is because team members from different technical backgrounds can all contribute to and understand the creation of a narrative scenario. Scenarios can also be used to motivate and direct a newly formed design team, and to facilitate external communication: ensuring consistency in the design vision and clearly communicating the state of a project to senior managers.
One of the limitations of a scenario is that it is intrinsically single-threaded: it does not immediately point out errors or better alternatives to either the design team or the user during testing. The way to overcome this disadvantage in the Exploratory Stage is to develop and test multiple, highly divergent scripted scenarios such that many alternative concepts are examined simultaneously.
In the Orbitor project, we developed a series of scenarios in combination with the ideation sketches discussed earlier. Brainstorming using an electronic whiteboard was an effective tool for this stage of design. We used the hard-copy capability of an electronic whiteboard to capture transient design ideas. As a graphical tool, the whiteboard was ideal for the rapid development of a graphics-based interface. With Orbitor, this method was used to optimize the interaction between the physical-product user interface and the screen-based user interface.
Early sketch-based scenarios are used as stimulus material in presentations and discussions with potential end users and senior management. From these sessions, the design team may then begin to define a list of the preliminary user values and user requirements for the product (see Figure 11.2). User values encompass the intended customers future needs, desires, and goals.
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