Example-driven modeling: on effects of using examples on structural model comprehension, what makes them useful, and how to create them

We present a controlled experiment for the empirical evaluation of example-driven modeling (EDM), an approach that systematically uses examples for model comprehension and domain knowledge transfer. We conducted the experiment with 26 graduate (Masters and Ph.D. level) and undergraduate (Bachelor level) students from electrical and computer engineering, computer science, and software engineering programs at the University of Waterloo. The experiment involves a domain model, with UML class diagrams representing the domain abstractions and UML object diagrams representing examples of using these abstractions. The goal is to provide empirical evidence of the effects of suitable examples on model comprehension, compared to having model abstractions only, by having the participants perform model comprehension tasks. Our results show that EDM is superior to having model abstractions only, with an improvement of 39\% for diagram completeness, 33\% for questions completeness, 71\% for efficiency, and a reduction in the number of mistakes by 80\%. We provide qualitative results showing that participants receiving model abstractions augmented with examples experienced lower perceived difficulty in performing the comprehension tasks, higher perceived confidence in their tasks\’ solutions, and asked 90\% fewer clarifying domain questions. We also present participants\’ feedback regarding the usefulness of the provided examples, their number and types, as well as the use of partial examples. We present a taxonomy of the different types of examples, explain their significance, and propose guidelines for manual and automatic creation of useful examples.