- Magnet Schools and Peers: Effects on Mathematics Achievement
Authors: Dale Ballou
This paper estimates the impact of attending a magnet school on student achievement in mathematics in a moderately large Southern district. Admission to magnet schools is through lotteries. Because lottery winners would have attended zoned schools of varying quality in the absence of magnet schools, the response to treatment is necessarily heterogeneous. Even so, these instruments are capable of identifying the effect of treatment on the treated for all students who enter magnets through the lottery. The researchers also exploit lottery outcomes to estimate the effect of peers on student achievement. Results indicate that race and income of peers have a substantial impact on achievement: the estimated difference between a school where students are 75 percent black and one in which students are 25 percent black is more than half a year’s normal growth in mathematics. Further analysis indicates that these peer characteristics are not proxies for other determinants of achievement, such as teacher quality or heterogeneity in the response to treatment.