Improving CRC-Card Role-Play with Role-Play Diagrams
San Diego Room
Monday, 15:30, 20 minutes
Jürgen Börstler, Umeä University
CRC cards are a lightweight approach to collaborative object-oriented modelling. They have been adopted by many educators and trainers to teach early object-oriented design. Reports in the literature are generally positive. So is our own experience. However, over the years, we have noticed many subtle problems and issues that have largely gone unnoticed in the literature.
In this paper, we discuss the problems and issues we experienced when teaching CRC cards to novices. Two major sources of problems can be traced back to CRC card role play. One is the usage of CRC cards as substitutes for actual objects during the scenario role-play and the other the difficulty to document or trace the scenario role-play "on the fly". We propose a new type of diagram to support the role play activities and to overcome these problems. Our experience so far is quite positive. Novices have fewer problems with role-play activities when using these diagrams. Teaching and learning the new type of diagram adds only little overhead to the overall CRC approach.
We also provide general guidelines for CRC card usage. Although our improvements are aimed at novices, we believe that the proposed diagram is useful even for professional software development.