A teacher's effectiveness--the most important factor for schools in improving student achievement--is not measured, recorded, or used to inform decision making in any meaningful way. The failure of evaluation systems to provide accurate and credible information about individual teachers' instructional performance sustains and reinforces a phenomenon that is called the Widget Effect. The Widget Effect describes the tendency of school districts to assume effectiveness is the same from teacher to teacher. This fallacy fosters an environment in which teachers cease to be understood as individual professionals, but rather as interchangeable parts. In its denial of individual strengths and weaknesses, it is disrespectful to teachers; in its indifference to instructional effectiveness, it gambles with the lives of students. Today, the Widget Effect is codified in a policy framework that rarely considers teacher effectiveness for key decisions. The fact that information on teacher performance is almost exclusively used for decisions related to teacher remediation and dismissal paints a stark picture: In general, schools are indifferent to instructional effectiveness--except when it comes time to remove a teacher. Better evaluation systems may offer a partial solution, but they will not overcome a culture of indifference to classroom effectiveness. Reversing the Widget Effect depends on better information about instructional quality that can be used to inform other important decisions that dictate who teaches in schools. In this article, the authors offer recommendations which outline a comprehensive approach to improving teacher effectiveness and maximizing student learning. If implemented thoroughly and faithfully, the authors believe they will enable districts to understand and manage instructional quality with far greater sophistication. Improved evaluation will not only benefit students by driving the systematic improvement and growth of their teachers, but teachers themselves, by at last treating them as professionals, not parts.