Group Work Learning Method is a cooperative learning technique that has positive effects in learning: students' active participation can increase both cognitive and social skills. Our work involved three cohorts of students of different years attending the same course at the University of Torino, Department of Psychology. The contents of the course were the same in all years, students were asked to form self-selected groups to find creative solutions to two cases regarding violent behavior in workplace. Satisfaction concerning this activity and the method to evaluate the performance of the activity were investigated. Findings confirm overall students' satisfaction related to group work learning method. This satisfaction improves the scores in course and teacher skills satisfaction. About the evaluation, findings shown that students agreed teacher's and peers' evaluation of the performance.