Methodology I: Task Analysis - Foundations for Designing User-Centered Systems - page 322

The results of a task analysis on their own will not tell you whether a particular
system or interface is acceptable or not. It just shows how well the system or
interface will work for particular tasks for particular people (in a particular con-
text). Decisions about modifications to the system or interface will often require
consideration of other factors, such as the resources that are available for further
development, other systems or interfaces (to cater for consistency and interoper-
ability, for example), and assumptions about the target users. Task analysis cannot
suggest whether novices should be served preferentially by the system, or whether
experts should be supported in an interface design, but TA can help compute the
costs and represent the trade-offs involved in making such decisions.
11.9 Other Resources
The Handbook of task analysis for human-computer interaction, edited by Dan
Diaper and Neville Stanton (2003), although 10 years old, still provides a fairly
comprehensive overview of TA. It makes a useful reference book, rather than
being something that you should read from cover to cover. A more general, but
still useful overview of the many types of TA and their application is Kirwan and
Ainsworth's A Guide to Task Analysis (1992) even though it is now over 20 years
old.
Clayton Lewis and John Rieman's shareware book, Task-Centered User
Interface Design (1994), www.hcibib.org/tcuid/ provides a useful expansion of the
material in this chapter, particularly on the role of task analysis in system design.
Shepherd's book, Hierarchical Task Analysis (2004), provides a detailed dis-
cussion of HTA. It illustrates how it can be applied to a wide range of tasks, and
how the results can generate a wide range of benefits.
For a practical guide to using CTA it is worth looking at Working Minds: A
practitioner's guide to Cognitive Task Analysis by Crandall et al. ( 2006 ). For
details about the sorts of methods that can be used in a CTA, it is worth consulting
Applied Cognitive Task Analysis in aviation by Thomas Seamster et al. (1997), and
Human factors methods by Neville Stanton et al. (2005).
David Kieras has papers, manuals, and tools covering the KLM, GOMS, and
task analyses available via his web site: www.ai.eecs.umich.edu/people/kieras/
kieras.html . You can also find several KLM calculators online. With these you
simply enter the KLM operators that are used to do the task, and the total time is
automatically calculated for you.
Kim Vicente's book Cognitive Work Analysis (1999) describes a broader,
integrated framework which includes models of the work domain, control tasks,
strategies social-organizational factors, and worker competencies. This framework
builds on the body of work called cognitive (systems) engineering which focuses
on the analysis, design, and evaluation of complex socio-technical systems.
The topic's web site has additional information on task analysis including some
tools.