This action research study summarizes the investigation of journal writing and cooperative grouping with 8th grade geometry students in the construction of proof. Students written responses to prompts in journals were analyzed over the course of twelve weeks. Case studies of four students were developed from the researchers’ three geometry classes. All four students in the study participated in an academic program called Pre International Baccalaureate Preparation. Standardized test scores and an attitude scale categorized the four students. The ATMAT survey (Appendix A) measured each student’s attitude toward mathematics. Writing prompts focused on the students’ perceptions of the group process in constructing proofs and the development of geometric proof. The results suggested the students were engaged in learning within their cooperative groups but they also desired individual time before coming to a group setting. In addition, students’ written responses to journal prompts may provide an informal assessment and help students convey their own understanding of proof before any formal assessments.