Can Achievement Peer Effect Estimates Inform Policy? A View from Inside the Black Box
研究发现，当同伴效应源于能力、努力等不可观测因素时，标准实证方法无法准确测量这些效应，且估计结果不能用于预测学生重新分班的效果。
Empirical studies of peer effects rely on the assumption that peer spillovers can be measured through observables. However, in the education context, many theories of peer spillovers center around unobservables, such as ability, effort, or motivation. I show that when peer effects arise from unobservables, the typical empirical specifications will not measure these effects accurately, which may help explain differences in the magnitude and even sign of peer effect estimates across studies. I also show that under reasonable assumptions, these estimates cannot be applied to determine the effects of regrouping students, a central motivation of the literature. © 2014 The President and Fellows of Harvard College and the Massachusetts Institute of Technology