The ability and competence to communicate with students in a clear and understandable manner is referred to as teaching effectiveness (Sanchez et al., 2020). Educators strive for ongoing professional development and skill enhancement as a means of improving student achievement, and there are standardized performance metrics used to observe how effective instruction affects student performance (Sanchez et al., 2020). State and local education planners work to assess and enhance the quality of instruction. To this end, state education authorities are working to provide clear, uniform standards for evaluating teachers' skill levels and efficacy as educators (Kraft & Gilmour, 2017). This study explored the connection between teacher evaluation scores and student achievement. The researcher gathered data spanning multiple grade levels and years at K-12 schools to paint a comprehensive picture. The researcher analyzed both teacher evaluation scores and student performance in reading, employing sophisticated techniques to account for external factors like student background. A power analysis MANCOVA indicated that the minimum sample size to yield a statical power of at least 0.8 with an alpha of 0.05 and a medium effect size (d = 0.5); therefore, the study utilized 74 teachers and their student data per grade band. However, the findings unveiled a surprising truth: there was no significant impact of teacher evaluation scores on student reading achievement, nor do teacher evaluation scores have any significant impact on teacher retention. This unexpected outcome challenges traditional assumptions and paves the way for further exploration into the multifaceted influences on student success, and the use of teacher evaluation to push evaluation to encompass more nontangible aspects as self-efficacy and a student's intrinsic motivations. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]