经济与社会科学2019nber.org
教师对学生成绩与身高的效应：一个警示性案例
Teacher Effects on Student Achievement and Height: A Cautionary Tale
入门 · 约 45 分钟读完前置知识：统计学基础、回归分析、教育测量概念
导读
这篇 NBER 工作论文研究基于'增值模型'(value-added measures)的教师效能评估是否可靠。作者用同样的统计方法分析教师对学生身高的'影响'，发现模型同样会得出教师能'让学生长高'的结论，说明这类模型很大程度上捕捉的是学生群体间的无关差异，而非教师的真实教学效果。
HN 关注点：许多学校正依据增值指标来奖励或考核教师，这篇论文用身高这一荒诞对照直接质疑了该方法的统计有效性，引发关于教育测量方法论的讨论。
HN 评论精选
这几条评论里：支持 1 质疑 1 补充 1 亲历 1
支持概括论文核心：增值模型测出的主要是学生群体差异，而非教师效果
摘要：学校正基于'增值指标'奖励教师，这些指标试图衡量教师对学生学业进步的影响。论文表明这些模型主要捕捉的是学生群体间无关的差异——方法是用同样的方式'奖励'那些学生更高的教师。
jefftk查看英文原文
Summary: schools are rewarding teachers based on "value-added measures" that try to measure the effect of the teacher on the student's educational progress. The paper shows that these models are mostly picking up unrelated differences between student populations, by showing that the same approach would reward teachers for having taller students.
亲历一线教师亲历：增值测量必然失败，目标管理扭曲整个教育系统
我在公立教育系统做了 15 年教师。增值测量注定失败。富裕地区学生起点高，学校请得起最好的老师，但提升空间本来就小；贫困地区学生起点低，学校只能请资质较差的老师，提升也有限。无论哪种情况，教师被测出的'效应'都很边缘，而统一考试是唯一被衡量的结果——这不代表教师不关心学生。增值指标只是作为教师绩效的目标管理被引入的。低龄教育阶段教师定下目标，小学教师为了显示增值而'刷数据'，层层向上传导，最终导致几乎每个孩子离校时都背负着不切实际的目标。推荐看 Adam Curtis 的《The Trap》了解目标管理的危害。
MarcScott查看英文原文
I worked as a teacher in, state funded, education for 15 years. Value added measurements of student achievement will always fail. In affluent areas, where student achievement is already high, schools can afford to hire the best teachers, but they will realistically only be able to boost achievement by a small fraction, given the child's prior attainment. In deprived areas, where student achievement is lower, schools can only afford to hire less qualified teachers, and the boost to achievement will be a small fraction of previous attainment. Either way, the measured effect that the teacher has will be marginal, while common standards and common testing are the only measured outcomes. This does not equate to the teachers not being invested in student outcomes, or trying their best for their students. Value added measures were only introduced as a form of target setting, for teacher performance. I'd encourage everyone to watch Adam Curtis' The Trap[1] to see the effects of target setting. Teachers in early years education set a target, then primary school teachers need to show value added so game the system to show improvement. This trickles up the system, and the net result is unrealistic targets for almost every child as they exit formal education. [1]https://en.wikipedia.org/wiki/The_Trap_(TV_series)
质疑质疑身高对照的严谨性，但认同教师效能难以从学生成绩中剥离
用身高做对照有个问题：已有证据表明高个子因隐性偏见而更成功。所以也许教师指标仍然有效，因为高个子学生本来就因系统中的其他偏见更成功？——我主要是半开玩笑。认真说，我认为基于学生成绩衡量教师几乎不可能，因为教师只是方程的一部分，父母和家庭环境才是更大的变量。如果孩子回家面对的是不给他们饭吃、说他们一无是处的父母，教师能做的很有限。
jedberg查看英文原文
The problem with using height is that there is already evidence that taller people are more successful due to hidden biases. So perhaps the teacher measures were still valid because all the tall people were more successful because of other biases in the system? I'm mostly just being cheeky here. To be clear, I still think it's nearly impossible to measure how good a teacher is based on student performance, since the teacher is only one part of the equation, the parents (and the student's home life) being a much bigger part of the equation. The teacher can only do so much if the child comes home to parents that don't feed them and tell them they are worthless.
补充调侃式补充：引用 BMJ 那篇关于降落伞缺乏随机对照试验的讽刺性论文
这本是引用那篇'降落伞有效性研究'论文的绝佳机会。
joshvm查看英文原文
This would have been a perfect opportunity to cite the paper about the efficacy of parachutes: https://www.bmj.com/content/363/bmj.k5094
历次讨论
- 2019Hacker News 讨论帖237 分 · 169 评
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