ConcurTaskTrees (CTT) is a notation for task model specifications used in the design of interactive applications, particularly within model-based user interface design.
The main features of CTT are: Hierarchical structure, which provides a large range of granularity in describing large and small task structures; Graphical syntax, which reflects the logical structure in a tree-like form; Concurrent notation, enabling flexible task ordering. In the field of human–computer interaction, task models describe the logical activities an application should support to help users achieve their goals. Methods have been developed to derive user interfaces for different platforms from CTT specifications. The last evolution has been the introduction of preconditions.
CTT has been applied in both academia and industry, particularly in domains such as enterprise resource planning (ERP) and safety-critical systems, including air traffic control.. SESAR Joint Undertaking. Archived from the original on 2020-11-30. Retrieved 2025-06-12. It has also been considered by the World Wide Web Consortium (W3C) for task model standardization.
Usability studies have been conducted on CTT, and it has been mapped into the Unified Modeling Language (UML).
Tool support The editing and analysis of task models is supported by the ConcurTaskTrees Environment (CTTE). The executable code is publicly available and free to download.
References
External links Leonel Nobrega, Jardim Nunes Nunes, Helder Coelho: "Mapping ConcurTaskTrees into UML 2.0", Interactive Systems Design Specification and Verification (2006), Volume 33, Issue 228. Springer. Pages: 237–248. Model-based User Interfaces Incubator Group: ConcurTaskTrees. Fabio Paternò: "Using ConcurTaskTrees for Designing New Interactive Applications in an Industrial Context", ERCIM News No.31 - October 1997.
Fabio Paternò: Publications Reporting Work in which ConcurTaskTrees (CTT) has been used. Ana Barbosa, Ana C.R. Paiva, José Creissac Campos: "Test case generation from mutated task models", EICS '11 Proceedings of the 3rd ACM SIGCHI symposium on Engineering interactive computing systems, pages 175–184. http://www.cubeos.org/lectures/W/ln_9.pdf D. Reichart, A. Dittmar, P. Forbrig, M. Wurdel: ", Interactive Systems. Design, Specification, and Verification. Lecture Notes in Computer Science Volume 5136, 2008, pp 92-95. Josefina Guerrero García, Jean Vanderdonckt, Juan Manuel González Calleros, Marco Winckler : "". Interactive Systems. Design, Specification, and Verification. Lecture Notes in Computer Science Volume 5136, 2008, pp 96-101. Marco Blumendorf, Grzegorz Lehmann, Sebastian Feuerstack, Sahin Albayrak: "", Executable Models for Human-Computer Interaction. Lecture Notes in Computer Science Volume 5136, 2008, pp 238–251. Dan Diaper, Neville E. Stanton, eds.: The Handbook of Task Analysis for Human-computer Interaction, 2004.