For many first-year engineering students at Ashesi University in Ghana, the project-based learning (PBL) approach they experience in Introduction to Engineering differs from the rote-based pedagogies they have previously experienced. The authors’ previous efforts to understand this pedagogy's impact on the students have relied on pre-post survey tools. For some responses, higher-than-expected scores on the pre-survey have been noticed. This study aimed to understand whether a different methodology, a retrospective pre-post survey, would yield similar results and what reasons may underlie any differences.
A mixed-method approach was deployed with students in the 2024 cohort of the course. They completed two surveys – one at the beginning (pre-survey) and one at the end of the course (retrospective pre-post survey). Five skill/perception categories were deployed with Likert-scale questions. T. tests revealed no statistically significant difference in the traditional pre-post analysis, while in the retrospective analysis, all five categories had statistically significant increases with small to medium effect sizes. Interviews with select respondents revealed self-assessment bias, as they tended to overestimate their skills at the beginning of the course. These results suggest that the retrospective approach may be better suited for studies on this target group.