Implementing complex thinking as a formative framework in engineering education: A longitudinal study across two integrative project-based courses

Mechanical engineering education increasingly requires instructional designs that prepare students to address complex real-world problems involving uncertainty, sustainability constraints, and sociotechnical design compromises. Within this context, complex thinking has been proposed as a formative framework to support integrative reasoning, system-level analysis, and informed decision-making beyond disciplinary boundaries. This study examines the implementation of complex thinking across two consecutive project-based courses: Integrative Workshop I (IW1) and Integrative Workshop II (IW2), within an undergraduate Mechanical Administrative Engineering program. A mixed-methods, descriptive–exploratory research design with sequential formative monitoring was employed. Data collection included Likert-type surveys administered at multiple stages, open-ended reflective responses, and analytical rubrics used to assess the technical performance and design quality of student-developed prototypes. Quantitative data were analyzed using descriptive statistics and dimension-level internal consistency measures, while qualitative data were examined through thematic coding and triangulated with performance-based evidence. Results indicate positive trends in system-level reasoning, multidisciplinary knowledge integration, reflective decision-making, and collaborative engineering practice. Comparisons between IW1 and IW2 reveal a progression toward more holistic and context-aware design approaches. Overall, the findings support the value of sequencing integrative, project-based courses for supporting the development of complex-thinking competencies in undergraduate engineering education.