The paper analyses the grades assigned by the professors of the University of Milan to their students at the end of written exams, comparing what happened in academic year 2018-19 and in academic year 2020-21, i.e., before and during the crisis caused by the COVID-19 pandemic. In March 2020, the lockdown closed the classrooms, stopping face-to-face interactions among professors and students: it became then necessary to identify possible scenarios for carrying on written exams online, suitably monitoring student behaviors, and to propose them to the University professors. Main purpose of the analysis reported in this paper is a preliminary evaluation of the effectiveness of these scenarios, through comparison of the grades the professors assigned to their students. [For the full proceedings, see ED639633.]