The ability to evaluate teachers accurately is indispensable for both the development of effective teachers and for student achievement. In this era of accountability, it is important school districts develop evaluation systems that comply with the propriety, utility, feasibility, and accuracy standards of the Joint Committee on Standards for Educational Evaluations. This study focused on a process evaluation of a new teacher evaluation program. While previous studies have been conducted from the teachers or the evaluators' perspectives, this study examined both perspectives. More than 1,500 teachers and 41 principals were invited to complete an online instrument modified from surveys conducted by Hopkins and Stronge. Of concern to the teachers and principals was the accuracy of the new evaluation program, they did not see the value and validity of using SLOs to improve teaching practices to increase learning, and teachers slightly favored using the professional practices component more than the SLO component of the evaluation. Using SLO data in teacher evaluation is an unknown dynamic for teachers; therefore, school administrators need to understand how teachers perceive this change as it relates to teacher support of the new evaluation process. If districts are to safeguard the fidelity, implementation, and sustainability of new evaluation programs for teachers, districts must acknowledge the influence teacher perceptions have on endorsing implementation efforts toward change. Teachers' perceptions toward adjusting instructional practices to align with the standards and criteria of new evaluation programs can either hinder or ensure program implementation. [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.]