A related study found a number of changes in the reflective stance of preservice teachers using a video case curriculum in a mathematics methods course. These included a higher level of reflection, an increased use of evidence, a shift from affective to pedagogical concerns, and increased attention to student thinking (Stockero, 2006). The quasi-experimental study reported on here investigates to what extent these changes in reflective abilities can be attributed to the video case curriculum by comparing the reflective skills of this group of preservice teachers to a group of their peers who were enrolled in the course before such a curriculum was introduced as an instructional tool. In many cases, the two groups' reflective abilities were similar; however, even in these cases, there were subtle, yet important, differences. In addition, the group who used the video curriculum showed significant gains over the comparison group in terms of their use of evidence and their focus on student thinking. Implications of these findings and recommendations for using video cases as an instructional tool in preservice teacher education are discussed. (Contains 10 tables.)