书面表达英语作文 青少年图书阅读量下降

Studies based on instrumental variable techniques suggest that the value of a high school education is large for potential dropouts, yet we know much less about the size of the benefit for students who will go on to post-secondary education. To help fill this gap, I measure the value-added of a year of high-school mathematics for university-bound students using a recent Ontario secondary school reform. The subject specificity of this reform makes it possible to identify the benefit of an extra year of mathematics despite the presence of self-selection: one can use subjects unaffected by the reform to control for potential ability differences between control and treatment groups.