School districts are confronting difficult choices in the aftermath of the financial crisis. Today, the financial imbalance in many school districts is so large that there may be few alternatives to teacher layoffs. In nearly all school districts, layoffs are currently determined by some version of teacher seniority. Yet, alternative approaches to personnel reductions may substantially reduce the harm to students from staff reductions relative to layoffs based on seniority. As a result, many school district leaders and other policy makers are raising important questions about whether~other criteria, such as measures of teacher effectiveness, should inform layoffs. This policy brief, a quick look at some aspects of the debate, illustrates the differences in New York City public schools that would result if layoffs were determined by seniority in comparison to a measure of teacher effectiveness.

We are in the midst of what amounts to a national experiment in how best to attract, prepare, and retain teachers, particularly for high-poverty urban schools. Using data on students and teachers in grades 3–8, this study assesses the effects of pathways into teaching in New York City on the teacher workforce and on student achievement. We ask whether teachers who enter through new routes, with reduced coursework prior to teaching, are more or less effective at improving student achievement. When compared to teachers who completed a university-based teacher education program, teachers with reduced coursework prior to entry often provide smaller initial gains in both mathematics and English language arts. Most differences disappear as the cohort matures, and many of the differences are not large in magnitude, typically 2 to 5 percent of a standard deviation. The variation in effectiveness within pathways is far greater than the average differences between pathways.