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Larry E. Wood
Brigham Young University, Provo, Utah
email: WoodL@byu.edu
1. GOOD INTERFACE DESIGN
Design is both a product and a process. The product is an artifact designed for a specific purpose, given a set of components, resources, and constraints within which a designer has to work. The process consists of techniques and procedures for constructing the desired product. While there are principles and laws that guide effective design, there is usually a certain amount of craft and creativity involved in producing effective designs.
Whether or not the design is effective obviously depends on the criteria used to define effectiveness. In his book The Design of Everyday Things, Norman (1990) makes a strong case for the need to emphasize usability (in addition to functionality and aesthetics) through the design of artifacts that we frequently encounter in our everyday lives (e.g., doors, VCRs, and automobiles). He does so by providing many examples of good and bad designs (from a usability perspective) and in listing attributes of artifacts that make them usable (e.g., providing visible affordances, providing feedback regarding actions performed, and preventing users from making errors).
The same principles and guidelines outlined by Norman can also be applied to the design of a software application, particularly the user interface, which is the focus of this book. To be usable, a user interface must provide access to the functions and features of an application in a way that reflects users ways of thinking about the tasks that a potential application will support. This requires that the application not only provide support for necessary aspects of the users work, but must also provide the means for them to interact with the application in ways that are intuitive and natural. Great improvements in the effectiveness of a user interface have been made during the last 15 years, through (1) the improved components and resources available in Graphical User Interfaces (GUIs), pioneered by such systems as the Xerox Star, precursor to the Apple Macintosh desktop and in Windows (Smith et al., 1982) and (2) in the transition from system-centered to user-centered design methods (Norman and Draper, 1986).
The Star and related GUI systems introduced new hardware resources and components, while the user-centered design orientation focused design methods on the potential users of an application. In essence, the new hardware and software resources provided the building blocks of more usable computer applications, while the user-centered orientation provided the impetus to develop methods to insure that the building blocks were used in ways that fit the users way of thinking about and performing their work. In this way an interface could be made more natural and intuitive than had previously been the case.
2. The Gap: Or Then a Little Magic Happens
By definition, user-centered design techniques focus on potential users (including their characteristics, their tasks, and their environment) whose work is to be supported by an application (i.e., functional requirements were developed from a users perspective and are referred as user requirements). Typical activities of a user-centered design development process are listed in Figure 1.1. It should be noted that, while an order is implied in Figure 1.1, a critical aspect of user-centered design is that it is iterative, as is emphasized in the chapters of this volume.
Figure 1.1. Typical activities in a user-centered design process.
Considerable effort has been expended to document methods related to each of the activities in Figure 1.1. In support of the activities for identifying users and determining their support requirements, there are sources discussing methods for gathering user information through field methods (e.g., Wixon and Ramey, 1996) and formal task analysis methods (e.g., Johnson, 1992). Furthermore, there are sources that emphasize the importance of representing work-related tasks via scenarios (e.g., Carroll, 1995) and use cases (e.g., Constantine, 1995). For producing potential designs, there are a variety of sources that provide guidelines regarding the important characteristics of a usable interface (e.g., Fowler and Stanwick, 1995) and for producing design prototypes using both low- (e.g., Monk et al., 1993) and high-fidelity methods (e.g., Hix and Shulman, 1991). Also, much has been written about the methods for evaluating a user interface, once it has been produced, either by expert review (e.g., Nielsen, 1993) or by formal testing with potential users (e.g., Dumas and Redish, 1993).
As indicated above, while there are some excellent sources of information on user interface design, none contains specific descriptions of how a designer transforms the information gathered about users and their work into an effective user interface design. This is indicated in Figure 1.1 by the question mark between User Requirements and Interface Designs. Some might argue that is to be expected because that process is a highly creative one and that creative processes are inexplicable by their nature. While this may be true in a limited sense, designs dont really appear as if by magic.1 They are largely the result of thoughtful, conscious processes, and the chapters in this volume represent an attempt to make more explicit just how designers bridge the gap.
1For more on this topic, the interested reader is referred to the Creative Cognitive approach (Ward, Finke, and Smith, 1995) which assumes that the same methods used to understand normal cognitive processes apply equally to the understanding and description of creative activities.
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