Higher education institutions aim to incorporate competency development into their engineering curricula, which can help engineering students become independent critical thinkers with entrepreneurial mindsets. However, no solid methods exist to evaluate the acquisition of these competencies. Such assessments’ objectivities are often ensured by distinguishing between who supervises a student group and who grades its project. The assessor’s active involvement in the learning process is essential for assessing competency development during the learning process, but such involvement may lead to assessor bias. This study aims to investigate whether and under what conditions coaches can be objective assessors. An intraclass correlation coefficient (ICC) was used to measure the level of agreement between assessors and coaches when using the same rubric to assess students’ deliverables. Four assessors and seven coaches from the University of Twente assessed 24 students’ individual learning processes based on individual reflection deliverables. The coaches assessed the students they supervised during a challenge-based learning (CBL) course, while the assessors were without participating in the learning process assigned randomly to students. The means were compared using SPSS, which indicated, among other things, that coaches generally awarded higher scores than assessors. This may indicate that coaches are biased because of their involvement in the learning process. Despite this, the results also indicate that coach assessment was in line with assessors when the coach was an appointed and experienced examiner