Economics of Education Review 31 (2012) 293–301 Contents lists available at SciVerse ScienceDirect Economics of Education Review jou rn al h om epa ge: www . elsevier.com/locate/econedurev Measuring the effect of charter schools on public school student achievement in an urban environment: Evidence from New York City Marcus A. Winters ∗ Department of Educational Leadership, Research and Foundations, University of Colorado, Colorado Springs, CO 80918, United States a r t i c l e i n f o Article history: Received 22 October 2010 Received in revised form 26 August 2011 Accepted 31 August 2011 JEL classification: I20 Keywords: Charter schools Competitive effects School choice a b s t r a c t This paper uses student level data from New York City to study the relationship between a public school losing enrollment to charter school competitors and the academic achieve- ment of students who remain enrolled in it. Geographic measures most often used to study the effect of school choice policies on public school student achievement are not well suited for densely populated urban environments. I adopt a direct approach and measure charter school exposure as the percentage of a public school’s students who exited for a charter school at the end of the previous year. Depending on model specification, I find evidence that students in schools losing more students to charter schools either are unaffected by the competitive pressures of the choice option or benefit mildly in both math and English. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction Charter schools have recently emerged as popular alter- natives to traditional public schools. Much attention has been paid in recent years to measuring whether students benefit academically when they attend charter schools. However, also of interest to researchers and policymakers is the effect that charter schools have on the performance of students who remain in the surrounding public schools. Charter school critics commonly charge that charters rob traditional public schools of their most promising and motivated students and the resources they need to pro- vide a quality education. Whatever success charter schools achieve, it is often claimed, comes only at the expense of traditional public schools. This paper adds to the research examining the impact of charter schools on the students who are “left behind” in tra- ditional public schools within a large urban environment. ∗ Tel.: +1 917 270 6154. E-mail address: mwinters@uccs.edu The popular approach to measuring the systemic effect of charter schools using geographic distance as a mea- sure of market exposure is appealing when studying the influence of charter schools across a state. However, it is a problematic proxy within diverse urban environments with densely packed populations. I utilize a more direct approach to measuring public school exposure to compe- tition from charter schools to study the systemic effect of charter schools in New York City, which is both the nation’s most populous city and home of its largest public school district. Focusing on the impact of charter schools on achieve- ment in urban public schools is important because cities have been particularly affected by competition from char- ter schools. In some urban centers, charter schools have grown so numerous that they have siphoned a consid- erable number of students from the traditional public school system. Since 1970, student enrollment in tradi- tional public schools in Washington, D.C., has dropped by two-thirds—from 150,000 to about 44,000 students—while the city’s charter schools now enroll about 28,000 students. Enrollment in Detroit’s public schools has declined by 45 0272-7757/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.econedurev.2011.08.014