Monday, November 12, 2018

Rising to expectations

A new working paper says:
We develop and estimate a joint model of the education and teacher-expectation production functions that identifies both the distribution of biases in teacher expectations and the impact of those biases on student outcomes via self-fulfilling prophecies. Our approach leverages a unique feature of a nationally representative dataset: two teachers provided their educational expectations for each student. Identification of causal effects exploits teacher disagreements about the same student, an idea we formalize using lessons from the measurement error literature. We provide novel, arguably causal evidence that teacher expectations affect students' educational attainment: Estimates suggest an elasticity of college completion with respect to teachers' expectations of about 0.12. On average, teachers are overly optimistic about students' ability to complete a four-year college degree. However, the degree of over-optimism of white teachers is significantly larger for white students than for black students. This highlights a nuance that is frequently overlooked in discussions of biased beliefs: less biased (i.e., more accurate) beliefs can be counterproductive if there are positive returns to optimism or if there are socio-demographic gaps in the degree of teachers' optimism; we find evidence of both.
I love this (because it fits my prior so nicely :) I went to a 2-year public math and science boarding school for 11th and 12th grade, and the education I got there was fantastic and clearly ahead of anything else available in the state. Of course many factors made that possible, including the selective admissions process, hiring of teachers with PhDs, having control over our entire daily schedules rather than just classroom hours, etc. But what stood out to me was the high expectations. The history teacher used to say "It's easy to raise expectations; what's difficult is raising performance" but on the contrary, I think raising expectations was the single most important trick OSSM pulled off, and it was able to do so credibly because of its unique position as an alternative school. Anyone who wasn't able to meet those expectations or who didn't like the inevitable slaughter of their GPA was free to go back to their home high school (and many did).

After OSSM I went to Caltech, another school that has no sympathy for those who can't keep up. The 4 year graduation rate at the time was only 77% (compared to 86% for Harvard) and 6 year rate was only 88% (compared to 98% for Harvard). This notoriously cost them the #1 position on the US News and World Report rankings after the weighting function was adjusted to put more emphasis on graduation rates. This practice certainly harms many students who were at the top of their high school classes, would have been at the top of their classes at other great universities, but struggled at Caltech. But on the flip side, this is a necessary consequence of having credibly high expectations, which are in turn critical for motivating educational achievement. I don't expect US News to quantify this nuance, but it's surely recognizeable, no?