As school districts locally and across the country struggle with serious budget shortfalls, teacher layoffs have become commonplace. Who to layoff and how districts make that decision has become an intense focus of debate when it comes to school funding and education quality. Should layoff policies be dictated by the “last in-first out” approach? Or should teacher quality govern decisions, and if so, how do you measure a teacher’s effectiveness? Locally, in regard to education funding crisis in Philadelphia, Governor Corbett has offered Philadelphia schools a much-needed, one time, emergency grant of $45 million if the Philadelphia Federation of Teachers agrees to several contract changes including seniority. The union has so far refused to negotiate on the issue saying that seniority rights are protections teachers deserve. University of Pennsylvania education professor RICHARD INGERSOLL’s research focuses on the character of elementary and secondary schools as workplaces, teachers as employees and teaching as a job. We’ve invited him to explain the roots of the seniority system and why it is such a hot-button issue when it comes to education policy and reform.