This mixed method study was a practitioner inquiry into the teacher evaluation system that was enacted as a result of Pennsylvania House Bill 1901 (Act 82 of 2012). The study was an effort to gain an in-depth understanding of (a) factors that led to the passage of the Act 82 teacher evaluation policy, (b) what the policy was intended to do, and (c) how the policy has been translated into actual practice. Data was collected via electronic survey and semi-structured interviews. Participants were currently practicing K-12 public school principals from Beaver and Washington counties which are located in southwestern Pennsylvania. There were 27 survey participants and 6 semi-structured interview participants. Results suggest principals accurately understand the teacher evaluation tool as an accountability measure. All of them received some type of training prior to and/or during initial implementation. Effective implementation of the tool appears to be dependent on the capabilities of the principals, most of the principals are the only evaluator for their teachers and the use of student data varies by principal. Data on professional development practices was inconclusive but suggests that principals and teachers have input in district professional development offerings. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]