Due to teacher shortages at the study site, teaching positions in the state that is the focus of this study are filled by alternate route (AR) teachers, who earned bachelor degrees in the fields that were not related to education and received teacher certification through alternative teacher education programs. Because there is limited information about the preparation and performance of AR teachers at the site of this study, the purpose of this sequential mixed methods project study was to explore AR teachers' preparation and their effect on student learning as measured by Northwest Evaluation Association's Measures of Academic Progress/Discovery Education Assessments. Guided by Mezirow's experiential learning theory and Dewey's educational philosophy, this project study investigated the relationship between the alternate route teachers' field experiences and years of experience, and teachers' effect on student learning. Data collection included a survey of 36 K-12 AR teachers selected through convenience sampling, document analysis of their student assessment scores, and 6 structured interviews with purposefully selected high performing AR teachers. Data were triangulated and cross-analyzed. Findings indicated that when AR teachers engage in field experiences prior to teaching, their students have higher levels of achievement as evidenced in their assessment scores. There was no correlation between AR teachers' years of teaching experience and their student assessment scores. Analysis of AR teachers' interview responses revealed a need for professional development, which was then created to address those needs. This study may contribute to social change by offering the targeted professional development of AR teachers and improving the design of AR preparation programs to better influence student learning. [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/en-US/products/dissertations/individuals.shtml.]