Increased attention on teacher accountability via student achievement gains has brought proposed policy changes which recommend teachers receive performance pay as recognition for effective teaching. In response to growing consensus that teachers' contributions to student learning should be a part of the teacher evaluation process, education reformers have begun implementing pay-for-performance models that reward teacher performance by the scores their students receive on high-stakes testing through the use of sophisticated value-added models. There is currently a broad scope of value-added models based on student academic achievement gains, and the majority of studies centering on these diverse models indicate little stability in teacher scores across time. This study takes into account the previous research on value-added growth models, and explores the uncharted territory of measuring teacher stability on state assessment scores in one midsize district over a longer period of time. Results from this study showed weak to moderate correlations from one year to the next in stability of teacher scores, with more stability evidenced in math than in reading. As a result of the instability of teacher scores over time, teacher characteristics attributed to stable and unstable teachers respectively could not be determined. [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.]