Introduction The role of reflection in experience-based learning is discussed widely. This paper researches the effects of a reflection assignment as part of debriefing with qualitative and quantitative methodology in five simulation game-based seminars. Research Design and Methods The intervention (reflection assignment) used in this study consists of three reflective questions that are discussed in groups. We aim to find out the effects of adding this intervention to the regular in-between-debriefings (three times during the whole seminar). The methodological setup is quasi-experimental and so, consisted of a test group and a control group. Two different types of simulation games were used, one a general management game and the other a change management game. Data used in this study is gathered from three different sources: First, we used in-game-performance data from both games. Second, we used two types of questionnaires to evaluate game experience and self-reported learning (MEEGA+ and ZMS inventory). Third, the reflection notes from the treatment-teams were used for qualitative analysis. Results In several dimensions (game-success, game-experience and self-reported learning) significant differences were found between treatment and non-treatment students. Qualitative data show a deep level of reflection for treatment teams differentiating for the two simulation games evaluated. Discussion Supported by the qualitative reflection data we assume that the better results for treatment-students are routed in the repetitive reflection. The permanent circular reflection helps treatment students to understand the games better and gain deeper insights.