Supporting collaborative learning and problem-solving in a constraint-based CSCL environment for UML class diagrams Nilufar Baghaei & Antonija Mitrovic & Warwick Irwin Received: 12 March 2007 / Accepted: 16 July 2007 / Published online: 5 September 2007 # International Society of the Learning Sciences, Inc.; Springer Science + Business Media, LLC 2007 Abstract We present COLLECT-UML, a constraint-based intelligent tutoring system (ITS) that teaches object-oriented analysis and design using Unified Modelling Language (UML). UML is easily the most popular object-oriented modelling technology in current practice. While teaching how to design UML class diagrams, COLLECT-UML also provides feedback on collaboration. Being one of constraint-based tutors, COLLECT-UML represents the domain knowledge as a set of constraints. However, it is the first system to also represent a higher-level skill such as collaboration using the same formalism. We started by developing a single-user ITS that supported students in learning UML class diagrams. The system was evaluated in a real classroom, and the results showed that students’ performance increased significantly. In this paper, we present our experiences in extending the system to provide support for collaboration as well as domain-level support. We describe the architecture, interface and support for collaboration in the new, multi-user system. The effectiveness of the system has been evaluated in two studies. In addition to improved problem-solving skills, the participants both acquired declarative knowledge about effective collaboration and did collaborate more effectively. The participants have enjoyed working with the system and found it a valuable asset to their learning. Keywords Collaboration support . Computer supported collaborative learning . Constraint-based modelling . Evaluation . Intelligent tutoring system . Problem-solving support . UML class diagrams Computer-Supported Collaborative Learning (2007) 2:159–190 DOI 10.1007/s11412-007-9018-0 N. Baghaei (*) : A. Mitrovic : W. Irwin Department of Computer Science and Software Engineering, University of Canterbury, Private Bag 4800, Christchurch, New Zealand e-mail: nilufar.baghaei@gmail.com A. Mitrovic e-mail: tanja@cosc.canterbury.ac.nz W. Irwin e-mail: w.irwin@cosc.canterbury.ac.nz