, a scenario
is a narrative describing foreseeable interactions of types of users (characters) and the system. Scenarios include information about goals, expectations, motivations, actions and reactions. Scenarios are neither predictions nor forecasts, but rather attempts to reflect on or portray the way in which a system is used in the context of daily activity.
Scenarios are frequently used as part of the systems development process. They are typically produced by usability or marketing specialists, often working in concert with end users and developers. Scenarios are written in plain language, with minimal technical details, so that stakeholders (designers, usability specialists, programmers, engineers, managers, marketing specialists, etc.) can have a common example which can focus their discussions. Scenarios are used in a number of ways:
- As a vision pieces. Vision pieces provide a high level picture of an envisioned system or product. One example is Apple's Knowledge Navigator video
- As an illustration of functionality: This type of scenario illustrates the functionality the system needs to support, often connecting it to the motivations and needs of the envisioned users of the system.
- Scenarios may focus on the value offered by a system, showing how it offers an advantage over the way things are. This type of scenario may be used to 'sell' an idea within the organization that is considering developing the system.
- Scenarios may be used in the context of research, to explore, at a detailed level, the functionality a system needs to have to succeed in its daily context of use.
Vannevar Bush's As We May Think essay is a famous example of a scenario that served as a vision piece. It was the user scenario that presented the idea of hyperlinks, and illustrated the value of hypertext. It described the (fictitious) Memex machine that inspired Douglas C. Engelbart to see the potential of the personal computer, and enabled him to secure the funding necessary to design the computer mouse and first graphical user interface in 1968.