Methodology I: Task Analysis - Foundations for Designing User-Centered Systems - page 321

Table 11.7 Ways to use TA to improve interfaces
1. Modify the interface to support all the tasks in the TA
2. Modify the interface to not support tasks not required by the task analysis
3. Modify the interface to do steps for the user where choices are not required
4. Modify the interface to use fewer actions
5. Modify the interface to use a simpler task structure
6. Modify the interface to provide more regular knowledge/interactions to perform related tasks
7. Modify the interface to not require holding state variables in the task analysis or user's head
8. Modify the interface to make common tasks faster
9. Modify the interface to make expensive tasks slower/harder to initiate
10. Teach any alternative methods through and in the interface
multiple ways that task analyses can be used and the savings they suggest, these
numbers are quite plausible.
The various forms of task analysis can be ordered by how much detail they
include. A preliminary classification can be into declarative and procedural rep-
resentations. The declarative representations merely denote the actions or tasks the
users will perform. The simplest of these are HTA and CTA. The KLM is a
slightly more complex example of this because it attributes time to each action.
Procedural task descriptions, such as advanced versions of GOMS (John and
Kieras 1996b ) and models in cognitive architectures (noted in the final chapter),
can include enough procedural knowledge of how to perform the task such that
they can also perform the task in some way, perhaps with a simplified version of
the interface. Declarative representations of behavior, like the KLM, for example,
will note that the result of a mathematical task is ''a number,'' whereas a fully
procedural task analysis will be able to compute the actual number. This chapter
discusses several examples of each type. There is a wide range of approaches, and
descriptions of them are available in surveys (Adams et al. 2012 ; Beevis 1999 ;
Schraagen et al. 2000 ), as well as in manuals and tutorials on these other TA
approaches.
As you use TA in a wider range of situations, you should become more skilled
in applying it. For specific situations you may want to look at some of the more
specialized forms of task analysis. For example, if you have many novice users,
you might create a situation where the user has to read the documentation to find
the commands, which means that your design should ensure that the knowledge of
how to use the interface is findable or transmitted to the novice through instruc-
tions, conventions, and other design elements. When you need to do more complex
analyses, for example, where error recovery or multi-tasking is important, you may
need to consult further material to find the most appropriate technique, as well as
investigate supplementary techniques such as knowledge elicitation (e.g., Ericsson
and Simon 1993 ; Kirwan and Ainsworth 1992 ; Schraagen et al. 2000 ; Shadbolt
2005 ; Shadbolt and Burton 1995 ).