Pensions are a promise made today of benefits to be received tomorrow. They reward employees, including public school teachers, who remain working in a system for extended periods, often for their entire careers. And they impose large costs on those who leave before reaching retirement eligibility--all in the hopes of encouraging them to stay. Today, however, few Americans remain at one job for their entire working lives, and teachers are no exception. Nationally, 17 percent of all teachers who started in 2007-08 were no longer in the classroom in 2011, and about 72 percent will leave before twenty years of service. The reality is that the traditional retirement systems currently in place for most public school teachers favor only a small number of them and penalize many others. Teachers provide an invaluable service educating children. Thus, an important policy goal is to ensure that teacher compensation, including pensions, works for all teachers. In this study, the author examines the timing of the crossover point for a new teacher from the largest public school district in each state as well as the District of Columbia. These fifty-one districts employ approximately 11 percent of the nation's teachers. The primary research question is: How long must a new teacher work until her retirement benefits are worth more than her contributions (the crossover point)? The results of this analysis can give new teachers in the districts that were studied a clearer sense of their contribution obligations as well as the return they might expect. It also provides useful information about whether teacher retirement systems work for all employees, their employers, and taxpayers. This report proceeds as follows: Section I explains the data and methods used for this analysis. Section II presents the findings. Section III discusses implications and policy recommendations. Three appendices are included. [Foreword by Dara Zeehandelaar and Amber M. Northern.]