R. Plösch, P. Haindl: Hierarchical Task Analysis and Constraints, Published as Technical Report (Siemens Corporta Technology - CCT Software Systems and Processes), October 2018, Munich. The report is not available to the public.


The TAICOS (Task-Interest-Constraint-Satisficing) method is a structured approach for elicitation of user tasks, and tailoring of non-functional stakeholder interests as constraints in the context of these tasks. Stakeholder interests may arise from engineering, operational, legal, business, or other attained objectives and express a broader non-engineering notion of interests towards software. The method allows to direct and balance development efforts to satisfice interests, i.e. to satisfy an interest sufficiently and not excessively. The moderation-based elicitation of user tasks is guided by prioritizing which functions provide value to the user and thus contribute directly to the business idea behind the envisioned software solution. Without individual tailoring of stakeholder interests, development and operational efforts undertaken for their fulfillment can only be satisfied uniformly across all functions. From an engineering perspective, this pinpoint specification of a constraint derived from an interest and also in relation to a task also guides software engineers. It tangibly outlines how an interest can be practically specified as a constraint and also satisfied on this fine-grained level. Specifically, legal interests can be taken into account more thoroughly as its operational and engineering impact for each task can be assessed individually. Taking a business perspective TAICOS fosters capturing the different stakeholders’ objectives through the elicitation of interests arising from their objectives and providing an overview for all participants about the provided core functionality and value for the user.