Despite the prevalence of student learning objectives (SLOs) in teacher evaluation systems throughout the United States, research on the validity of student and teacher SLO scores used for high-stakes decisions is lacking. For this reason, this dissertation is comprised of two chapters that examine student and teacher-level SLO performance data from select districts in one Race to the Top state. In Chapter 1, I describe the quality of student assessment data and the comparability of student scores across alternative growth targets. I find that in the first year of implementation, assessments from half of the courses in the sample contained indicators of poor data quality, including anomalous score distributions and small to negative correlations between student prescores and postscores. However, in the second year of implementation, when student SLO performance is incorporated into final teacher evaluation scores, far fewer assessments contained anomalous score distributions, and there is no evidence to suggest manipulation of student scores. In addition to the assessments, the choice of student growth target does have an impact on the comparability of student and teacher scores across districts and years. Chapter 2 describes the validity and reliability of teacher SLO scores. I find that while teacher SLO scores are moderately stable across courses, they are not stable over time, likely due to changes made to the assessments and targets used to determine student SLO scores. Further, for teachers with both SLO scores and an alternative metric of performance based on student growth, the two metrics do not converge. Finally, teachers in courses with higher average student prescores and lower proportions of students with disabilities have slightly higher SLO scores. In general, results on teacher SLO scores were similar to those found with value-added based metrics of teacher performance. Findings from both chapters suggest that improvement in the quality of the assessments administered as well as greater consistency in the growth targets assigned to students, both within districts over time and across districts, will improve the validity of student and teacher SLO scores in this state. [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.]