Introduction
The COVID-19 pandemic has impacted university teaching worldwide. Within a very short time, universities had to convert their face-to-face courses to digital formats. Meanwhile, many universities are returning to face-to-face teaching, which inevitably raises the question of whether and to what extent to return to conventional formats as well. Several surveys show that students would like to see a combination of face-to-face teaching and digital approaches, such as blended learning (Amir et al. Our main intervention was conducting the first PbL session as a written Internet chat instead of an on-site meeting, i.e. only the communication channel was different. Our study therefore aimed at collaborative learning in the broader sense of a non-inferiority study compared to conventional PbL (cPbL), which throughout takes place on site. We analysed student evaluation data, results in a final summative single-choice exam, as well as attendance of lectures on site and use of lecture videos. Furthermore, we performed a qualitative analysis of student statements made in semi-structured group interviews about pros and cons of the blended PbL approach.