Using Examples for Teaching Software Design: An Experiment Using a Repository of UML Class Diagrams

Context: This research is positioned in the field of methods for creating software design and the teaching thereof. Goal: The goal of this research is to study the effects of using a collection of examples for creating a software design. Method: We ran a controlled experiment for evaluating the use of a broad collection of examples for creating software designs by software engineering students. In this study, we focus on software designs as represented through UML class diagrams. The treatment is the use of the collection of examples. These examples are offered via a searchable repository. The outcome variable we study is the quality of the design (as assessed by a group of experts). After this, all students were offered the opportunity to improve their design using the collection of examples. We ran a post-assignment questionnaire to collect qualitative data about the experience of the participants. Results: Considering six quality attributes measured by experts, our results show that: 1) the models of the students who used examples are 18% better than those of who did not use examples. 2) the models of the students who did not use examples for constructing became 19% better after updating their models using examples. We complement our statistical analysis with insights from the post assignment questionnaire. Also, we observed that students are more confident about their design when they use examples. Conclusion: Students deliver better software designs when they use a collection of example software designs.