A random sample of students who took the ACT test in either April or June of 2016 were invited to participate in an online survey via an email invitation (N = 35,0471). To study whether mailing post card invitations to students improves response rates, a portion of these test-takers were randomly assigned to be sent a post card. In addition, students who were sent a post card were randomly assigned to either receive one that pictured a female student or one that pictured a male student. All post cards described the research study and provided the student with the survey link. All groups received similar invitation via email. Three research questions were investigated: (1) Does sending a post card to students' improve response rates; (2) Does the picture on the post card have an impact on response rates; and (3) Does the picture on the post card have a differential impact on response rates based on the gender of the survey respondent? This is part of a larger study (N = 58,559) seeking to understand the impact that financial incentives and post card invitations had on response rates. Only the effects of post card invitations are provided in this report. Students were randomly assigned to receive either the post card or the incentive, but not both.