… is used to build a hierarchy of sub-tasks from a task. It was originally used in manufacturing industry to create good training steps. CS-students might think of the result of HTA as a tree, where the nodes are sub-tasks which consist of input conditions (necessary to activate node) and actions, which both together achieve the goal, leading to a feedback.
You might use four heuristic questions to fine-grain sub-tasks:
- paired actions: Are there additional actions which complete one action?
- restructure: Can I merge two similar sub-tasks?
- Balance: Are all sub-tasks similarly abstract?
- Generalize: Can sub-task be rephrased to its repeatable?
Sources
[1] Annett, J. (2003). Hierarchical task analysis. In E. Hollnagel (Ed.), Handbook of Cognitive Task Design. (pp. 17-35). Erlbaum Mahwah, NJ. https://mycourses.aalto.fi/pluginfile.php/614499/mod_resource/content/1/Annett_2003.pdf
[2] Müller-Birn, C., Vorlesung „Human-Computer Interaction I“, Foliensatz „Conceptual Models: Task Focus“
(von Daniel Stachnik)