RESEARCH METHOD • SYNTHESIS / ANALYSIS TECHNIQUE
84 Task Analysis
Task analysis breaks down the constituent elements of a user’s work flow, including actions and interactions, system response, and environmental context.
Traditional task analysis holds a scientific view of human interactions within systems, isolating key elements of human behavior, product or system behaviors and responses to human actions, the provision of system feedback, and the context in which tasks occur. Such analyses are usually expressed formally in flowcharts or other structured visuals, indicating tasks and subtasks, key decision points, and human-system response cycles. This analytic process stems from time and motion studies in industrial engineering, scientific management, and early human factors.1
While this level of formal task analysis can play a critical role in understanding user behaviors in context, designers will more typically employ a broader definition of the method, incorporating a blend of qualitative and quantitative approaches to gain insight into user and task processes.2 Task in this sense is not isolated to mean completion of a specific job, but rather encompasses a broad definition of any physical actions and mental processes as activities used to achieve goals, and information flows within the system environment. Task analysis is useful for all design disciplines, with relevant applications ranging from navigation of print documents and software device interactions to wayfinding in the built environment.
Task analysis is similar to contextual inquiry, because they employ many of the same methods, including observation and interviews. However, the difference is in focus, with contextual inquiry being more inclusive of general aspects of user behavior, decision making and interactions within the wider context, and task analysis concentrating solely on the task at hand. Interviews and observations specifically target user options, tools available, and choices made; decision points; identification of common mistakes and corrections; process inputs and outputs; frequency and importance of the tasks; and risks of failure.3
Task analysis can be deciphered using task decomposition, breaking the task down into component actions, and Hierarchical Task Analysis (HTA), identifying tasks and subtasks, categorizing them, and checking the accuracy of the model.4 Actions in task decomposition can be usefully organized by categories, such as purpose, cues, objects, method, and options.5 Putting the actions that constitute a task into a hierarchy ordinarily results in the familiar tree diagram or other forms of flowcharting, which can then be verified by walk-through tests by those familiar with the task. A simpler yet less thorough version of task analysis can be completed using sticky notes to identify and organize basic task actions, similar to the process of constructing affinity diagrams.6
1. Crystal, Abe, and Beth Ellington. “Task Analysis and Human-Computer Interaction: Approaches, Techniques and Levels of Analysis.” Proceedings of the Tenth Americas Conference on Information Systems, 2004.
2. Hackos, JoAnn, and Janice Redish. User and Task Analysis for Interface Design. New York: Wiley, 1998.
3. Kuniavsky, Mike. Observing the User Experience: A Practitioner’s Guide to User Research. San Francisco, CA: Morgan Kaufmann, 2003.
4. See note 3 above.
5. Kirwan, B., and L. K. Ainsworth. A Guide to Task Analysis. London; Washington, D.C.: Taylor and Francis, 1992.
6. See note 3 above.
A task analysis grid visualizing stakeholder scenarios and prioritized tasks. Each column starts out with a scenario, describes a task, and is followed by all the subtasks necessary to complete the task. The sub-tasks are color-coded and prioritized.
Courtesy of Todd Zaki Warfel, Principal Designer, messagefirst | design studio
