The purpose of this study is to analyze portfolio assessment results for two consecutive undergraduate interdisciplinary (civil and mechanical engineering) project-based learning engineering design courses. Based on those learning outcomes which both courses have in common, trends in changes of results are identified, quantified and interpreted. The findings show that the results improved considerably regarding two learning outcomes (Incorporating a systems approach based on a sustainability framework; Identifying, justifying and applying technical knowledge and skills), clearly worsened regarding one learning outcome (Applying techniques of project management), and didn’t show clear trends in the remaining five learning outcomes. Educators need to be aware that reaching anticipated learning outcomes seems to be more strongly influenced by the focus of engineering design projects (i.e. planning versus implementation) than the repetitive nature of these learning outcomes. Therefore, identical learning outcomes in consecutive engineering design courses cannot be considered a redundancy; rather they constitute a necessary re-enforcement within the framework of a different design project.