Research supports the importance of teacher quality on effective student learning. School districts recognize this fact and focus extensively on hiring quality teachers and improving teaching skills through professional development programs. Amazingly, despite common sense and a vast amount of research that reflects that employee performance is a function of both employee ability and employee motivation, school districts direct little focus on teacher motivation in their quest to improve teacher effectiveness. In fact, this researcher can think of no work environment that places less emphasis on employee motivation than Illinois public schools. There exists almost no relationship between what a teacher puts into their job in terms of effort and effectiveness and what they get out of their job in terms of compensation and performance evaluation. In fact, 83% of all school districts in Illinois have never given an "unsatisfactory" evaluation to a tenured teacher and 98.7% of school districts don't consider employee performance when determining compensation levels. This fact is at the core of this study. Employees compare what they receive from the organization (recognition, praise, financial rewards) and what they give to the organization (effort, skill, commitment, enthusiasm) to what their co-workers receive from and give to the organization. Research in equity theory has shown that the way individuals react to this type of situation may be based on their level of equity sensitivity. Equity sensitivity levels are a major predictor in the value of the individual within an organization. In an environment where the most effective, hardest working teacher and the most apathetic, least effective teacher will likely to be similarly recognized, equity sensitivity levels can be of particular significance in determining teacher effectiveness. This study will examine whether the level of equity sensitivity within teachers changes throughout their career. The study will also test whether the level of equity sensitivity in high-performing school districts differs from the level of equity sensitivity in low-performing school districts. If equity sensitivity changes throughout a teacher's career or if equity sensitivity exists at statistically different levels in high-performing and low-performing school districts, greater focus must be made on this characteristic as a way to improve student achievement through improved teacher performance. [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.]