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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 user’s ability to view and work with details of one apartment. We knew that:

  There is a considerable amount of information stored about each apartment (more than could fit on one screen).
  The overall goal of the design was to minimize the total number of windows.

Idea generation gave us two main ideas:

1.  Show detailed information about the selected apartment in one window and provide buttons in that window to open modal dialogue boxes containing further details.
2.  Show all details about the selected apartment in one window, and organize the information using tabs.

The results of reflection about the first main idea were:

  The user will experience fast initial access to details about the apartment because a small amount of data is loaded from the database on any particular request.
  It will constrain the users into a sequence for information access and require them to perform the following two actions to view additional items of information: cancel the open dialogue and open the next one.

The results of reflection about second main idea were:

  The user will be able to access all object data in one window instead of being required to open secondary windows. The desired information is only one “tab-click away”.
  Loading all object data from the database will require a relatively long time, and the user may become frustrated while waiting.

Decision result:

  Neither of the two ideas were acceptable, so we decided to return to generating ideas.

New idea generation:

  We felt that our first idea was the least acceptable, so we concentrated on improving the second one. Its main weakness was the technical constraint of the time to load data. The alternatives for improvement were:
1.  Create separate operating system processes for each tab so that they will be filled while the user is working with some other tab.
2.  Delay reading the information related to each tab until the user selects that tab.
3.  Load all the object data and show the tab with the most preferred information first. The user could then view, but not interact with, the information for that tab while waiting for the remainder of the apartment information to be loaded.

Reflections about alternative 1:

  This idea was impossible to implement with the development tools used in this case.

Reflections about alternative 2:

  The user may be frustrated by the delay when switching between tabs.

Reflections about alternative 3:

  If we could be certain that the most preferred information rarely changed and that the user required time to read it before interacting with it, the solution might be acceptable.

Decision result:

  We chose alternative number 3 because we believed that the user would be more willing accept an initial delay, rather than having occasional delays later. We also found that the most preferred information took the longest to load from the database, so the other parts could be loaded sequentially. Choosing alternative number 3 also required choosing main idea number 2, because that idea was the basis for alternative number 3.

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:

  Information modeling
  Design evaluation
  Technical writing
  User training and support


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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