The No Child Left Behind Act imposes sanctions on schools if the fraction of students demonstrating proficiency on a high-stakes test falls below a statewide pass rate. While the motivation behind this system is improved public school performance, it also provides incentives for schools to focus educational resources on the marginal student rather than those on the tails of the ability distribution. Using statewide, student-level panel data, students on the tails of the ability distribution, especially high-ability students, are demonstrated to score below expectations if their school is in danger from No Child Left Behind sanctions.