OPTIMAL GRADING
将师生关系建模为委托代理问题，教师关心人力资本形成，学生关心能力信号。区分评分规则是否可被劳动力市场观察，发现分数压缩和膨胀等常见现象在规则不可观察时均与最优能力筛选一致。
The teacher–student relationship is modeled as an agency problem, where teachers are concerned with human capital formation and students with ability signaling. We distinguish between two cases depending on whether in ability inference the job market can or cannot observe the grading rule applied. We show that many empirical grading patterns, including grade compression and inflation, are all consistent with optimal ability screening when grading rules are unobservable. With observable grading rules, the teacher perfectly screens students' abilities, provided that certain conditions hold. We apply the model to discuss policy applications such as “No Child Left Behind.”