This mixed-methods case study focuses on the third through fifth grade classrooms at a public elementary school in a Midwestern urban school district where the Northwest Evaluation Association's (NWEA) Measures of Academic Progress (MAP) assessment is being implemented. According to the school district, the goals of these tests are: to show student growth in meeting the state benchmarks, to identify student strengths and weaknesses, and to provide teachers with information to direct content and pedagogy. Unofficially, another goal seems to be to hold classroom teachers accountable for the progress of their students by providing them with data on student concept attainment and measuring student improvement over the year. Since the district and the NWEA stress the importance of utilizing these test results at the classroom level, the purpose of this research is to identify how MAP testing and the application of the test results are (or are not) utilized to inform mathematics instruction at the classroom level and to explore the effects of additional, external testing, particularly the effects on the teachers and students. Additionally, while the schools in the district do not have the option to exclude themselves from participation in this mandated testing program, a summative question as to the actual value of (or need for) the information provided by MAP testing will also be explored. Based on the results of this study, a more generalized understanding of the effects of additional, external standardized tests is also discussed. This study, in particular, adds a unique perspective to the current literature on external testing because, unlike previous studies that have focused on state-mandated standardized tests, this study focuses on a district-mandated test that is used in addition to the state-mandated testing. Along with the current body of literature on assessment, this study can inform educational policies that challenge the culture of testing - the culture of data, pressure, and confusion - that is present in classrooms and schools throughout the country. [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.]