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2.3. MAKING A DESIGN DECISION
One of the most challenging tasks of design is deciding among the plausible alternatives. This is because there is seldom one correct solution to a problem and choosing one design means rejecting many others. Making the decision often means striking a reasonable compromise among users needs, technical considerations, the context of use, and the business situation. If reflection suggests that none of the ideas are acceptable, it is necessary to return to generating ideas.
2.4. AN EXAMPLE OF BRIDGING THE GAP
We will present a short example to demonstrate how we usually bridge the gap several times. The example is a GUI system for apartment administration. The users needed to search for and access information about apartments (e.g., availability, rates, size). We had decided on a design where a window on the left contained a list of apartments and a window on the right listed detailed information about an apartment selected from the list (see Figure 6.2).
Figure 6.2 Apartment system design.
The focus of the design work was on the users ability to view and work with details of one apartment. We knew that:
Idea generation gave us two main ideas:
The results of reflection about the first main idea were:
The results of reflection about second main idea were:
Decision result:
New idea generation:
Reflections about alternative 1:
Reflections about alternative 2:
Reflections about alternative 3:
Decision result:
We later asked the users to perform real work tasks to evaluate our choice between design alternatives 2 and 3.
3. DESIGN CONTEXT
As interaction designers we have found that two key questions need to be answered before design can begin. (1) What are the desired effects of this system? and (2) What attributes are needed for the system to produce those effects? We are convinced that the C & R analysis must be performed prior to the start of the interaction design (see Ottersten and Bengtsson, 1996; Nilsson and Lachonius, 1996). Otherwise, those questions will surface later, during the system development process. Therefore, we have developed a method that ensures that these key requirements are defined before interaction design begins.
Interaction design and C & R analysis are two of the activities in what we call external design (see Figure 6.3). The other activities are:
Figure 6.3 The iterative process of external design.
We use the term internal design when discussing activities contributing to a good technical realization of the system. The contents of external design are contained in our two methods for usability work, AnvändarGestaltning©,1 and VISA©.1
1Registered trademark of LinnéData Management AB.
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