This study was conducted to examine the relationships between student achievement, as measured by Arizona's Instrument to Measure Standards, and teacher-assigned grades within a large, urban Phoenix, Arizona school district. For the quantitative component of the study, a proportionate stratified random sample of 3rd grade students from schools within three different socio-economic categories had their reading and math scores compared to their report card grades during the 2011-2012 school year, and relationships were identified. Further, survey research was conducted using open-ended questions to solicit data from both teachers and administrators from schools within the same demographics. After applying qualitative data analysis strategies, emergent themes were identified and examined for relationships to the qualitative results. The results of this study indicated that significant correlations existed between letter grades and AIMS performance for third graders in both reading and math. Further, a significant correlation was demonstrated between standards-based scores and AIMS performance in math, but not in reading. Teachers and principals expressed a variety of beliefs about the relationships between the performance indicators; however, general attitudes did not indicate the strength of correlations found between the quantitative data sets. In examining both the quantitative and qualitative results, differences were identified in correlations coefficients as well as beliefs across socioeconomic categories. [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.]