The Effects of Layout on Detecting the Role of Design Patterns

A controlled experiment investigating the effect layout has on how students identify design pattern roles in UML class diagrams is presented. Two layout schemes, multi-cluster and orthogonal, are compared with respect to three open source systems and four design patterns. Seventeen students were asked a series of eight design pattern role detection (comprehension) questions for each layout, followed by eight preference rating questions. Results indicate a significant improvement in role detection accuracy with the multi-cluster layout for the strategy pattern and a significant improvement in detection time with the multi-cluster layout for all four patterns. Preference ratings significantly favored the multi-cluster layout for pattern role detection ease. These results can be used to help improve the teaching of design patterns.