Abstract

Design rationale is the justification behind a product component, often captured via written reports and oral presentations. Research shows that the structure and information used to communicate and document rationale significantly influence human behavior. To better understand the influence of design rationale on engineering design, we investigate the information engineers and designers include in design rationales in written reports. Eight hundred and forty-six pages of student engineering design reports from 28 teams representing 116 individuals were analyzed using a mixed-methods approach and compared across project types. The rationales from the reports were coded inductively into concepts and later applied to five industry reports consisting of 218 pages. The findings reveal a spectrum of rationales underpinning design decisions. Grounded in the data, the feature, specification and evidence (FSE) framework emerged as a feature-based and low-effort capture approach. We discuss the need to improve design communication in engineering design, through structuring rationales (i.e., using the proposed FSE framework or other representations) and improving technical writing skills. Lastly, by enhancing design rationale communication and documentation practices, significant benefits can be realized for computational support tools such as automatic rationale extraction or generative approaches.