Student evaluations of teaching (SET) are an influential -- and often sole -- tool in higher education to determine course and teacher effectiveness. It is therefore problematic that SET results are disturbed by low response rates and response quality. An important factor discussed in prior research to increase SET effectiveness and students' motivation to participate is transparency about how their feedback is being applied in practice. The current study is the first to empirically test effects of transparency in a quasi-experimental field setting. After students filled in the SET, the intervention group was given a summary of the students' comments and how the teacher will use these to improve the course. We examined student participation on subsequent course evaluations. In contrast to our expectations, there was no significant improvement in response rates nor response quality between the intervention and control group. Furthermore, perceptions of meaningfulness did not significantly differ between the control and intervention group. This study indicates that more empirical research is needed to define the conditions under which transparency influences student participation. Further implications and recommendations for future research are discussed.