This study examines the differences between spacing of instruction and the classroom involvement of a cross-ability peer tutor on mathematical achievement in a developmental mathematics course. Grounded in spacing effect theory, this study examines how variations in the frequency of instruction affect student learning. The study consists of two segments conducted sequentially, specifically a quantitative analysis that was further supported by a qualitative inquiry. Results of the strong quasi-experimental study show that the mathematical achievement of students whose class met once per week for two hours was significantly lower than those students whose class met for one hour, twice per week. Through the use of student panel interviews, an interview with the cross-ability peer tutor and another with the faculty member, the qualitative findings suggest that many students may prefer the convenience of condensed class schedules that minimize their time spent on campus. For students enrolled in a developmental mathematics program at the collegiate level, these condensed scheduling options, however, may sacrifice learning for convenience. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]