Mathematics teachers are both more difficult to attract and more difficult to retain than social sciences teachers. This fact is not unique to the United States; it is reported as being a problem in Europe as well (Howson, 2002). In the United States, however, the problem is particularly preoccupying. Because of the chronic teacher shortages and retention problems in urban schools, researchers and scholars note that urban school administrators are often forced to utilize band-aid strategies, such as filling teacher vacancies with under-qualified, unqualified, or full-time substitute teachers (Hunter-Quartz, 2003). Though the severity and extent of the teacher shortage are well known, what is less certain is why the teacher shortage is so acute and persistent, despite the extensive research that has been conducted in an effort to understand it. This unresolved question is especially relevant for newer teachers, whose attrition rate is alarmingly high (Inman & Marlow, 2004). For this reason, research is needed that can describe and explain teacher shortage and its related phenomena so that interventions can be designed and implemented in an effort to staff the nation's schools with the quantity and quality of teachers needed to educate the current generation of students. The research proposed here is intended to be one such study. The proposed study focuses specifically on understanding the reasons behind the shortages of qualified mathematics teachers in resource-poor urban schools. It is hoped that the results of this study can provide insight into the nature of the problem and offer concrete solutions to begin staffing schools adequately. Therefore, the researcher proposes one major question which is the focus of this study. The research question is: What factors influence the retention of mathematics teachers in hard-to-staff urban schools, who are considered mid-career changers and who completed an alternative teacher certification program? [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]