In 2010, the federal government increased accountability expectations by placing more emphasis on monitoring teacher performance. Using a model that focuses on the New York State teacher evaluation system, that is comprised of a rubric for observation, local student assessment scores, and student state assessment scores, this descriptive-comparative research study investigated the impact a new teacher performance evaluation system has on student achievement in the first year of its implementation. The sample participants for the study were third through eighth grade English/Language Arts teachers and Math teachers who were evaluated utilizing a new quantitative teacher evaluation system. This descriptive-comparative study found that students of more effective teachers had significantly higher achievement in both Math and ELA classrooms in grades three through eight compared to students who were taught by ineffective teachers as measured by the newly implemented New York State teacher evaluation system. [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.]