Many students at an urban vocational high school have failed to pass the mathematics section of the New Jersey high school graduation assessment. Students who fail the graduation assessment are in danger of not earning their high school diploma. The purpose of this study was to learn, from the instructors' perspectives, why students were not achieving expected goals and what should be done to improve students' learning of mathematical concepts. The development of the project was based on a constructivist conceptual framework which supports improved student achievement in mathematics by taking into account a teacher's unique perspectives and promoting collaborative problem solving using researched-based practices. An anonymous, online survey questionnaire containing multiple choice and short response questions was used to examine 12 teachers' perspectives of reasons for low achievement in mathematics. A qualitative case study design was used to collect data and codified using qualitative metasynthesis. Coded themes were grouped, counted, and averaged. Peer assistance was enlisted to ensure trustworthiness of data collection and analysis. According to study findings, mathematics instructors perceived that student engagement, professional collaboration, and differentiated instruction could help improve student achievement in mathematics. Based on these findings, a proposal for a professional development intervention was created to train mathematics instructors to design lessons that engage students in mathematics learning and to differentiate instruction in a mathematics classroom. The potential for social change includes improved teacher pedagogy for mathematics instructors, increased graduation rates for urban youth, and enhanced college and career readiness for students who are graduating from vocational high schools. [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.]