Hierarchical Task Analysis
“As UX professionals, we have a great many analytical and descriptive tools available to us. In fact, there are so many that it can sometimes be difficult to decide which tool is most appropriate for a given task! Hierarchical task analysis (HTA) is an underused approach in user experience, but one you can easily apply when either modifying an existing design or creating a new design.” (Peter Hornsby – UXmatters)