Abstract
Context: Open Source is getting more and more collaborative with industry. At the same time, modeling is today playing a crucial role in development of, e.g., safety critical software. Goal: However, there is a lack of research about the use of modeling in Open Source. Our goal is to shed some light into the motivation and benefits of the use of modeling and its use within project teams. Method: In this study, we perform a survey among Open Source developers. We focus on projects that use the Unified Modeling Language (UML) as a representative for software modeling. Results: We received 485 answers of contributors of 458 different Open Source projects. Conclusion: Collaboration seems to be the most important motivation for using UML. It benefits new contributors and contributors who do not create models. Teams use UML during communication and planning of joint implementation efforts.