Group work is an excellent way to provide students with more complex, engaging class projects and help them practice many of the soft skills necessary for industry, where large-scale projects have long been the norm. However, as instructors of large CS classes are typically unable to determine individual contributions based on project submissions alone, group work can often cause some frustration when partners of the same group don’t put in the same amount of effort yet receive the same score.

In this paper, we describe a bimodal assessment strategy for group work, which couples end-of-term staff-led oral interviews with per-project student-reported self and peer evaluations. The combination of these approaches ensures a thorough and fair evaluation of students’ contributions to their groups, and scales up to large classes with limited instructional staff. The feedback from students is very positive, both in terms of agreeing with the narratives justifying this assessment strategy and finding it to be an effective solution to fairly grading group work.