(Guest Post by Collin Hitt)
Some teachers are better than others when it comes to raising test scores, which in turn can raise students’ earnings in adulthood. But test scores aren’t everything. A new study looks at whether individual teachers can have similar impacts on suspension rates, school attendance, GPA and even graduation rates. It finds that they can, and do.
To put the non-test score estimates into perspective, having an Algebra or English teacher 20 at the 85th percentile of GPA quality versus one at the 15th percentile would be associated with 0.09 and 0.054 higher GPA, respectively. For both subjects, a teacher at the 85 percentile of ontime grade progression quality versus one at the 15th percentile would be associated with being 5 percentage points (0.14σ) more likely to enroll in 10th grade on time. Given that not enrolling in 10th grade is a strong predictor of dropout, this suggests significant teacher effects on dropout…
That’s from Northwestern’s Kirabo Jackson, His working paper uses state-of-the-art value-added methods to identify North Carolina high school teachers who have significant impacts on test scores. He then uses the same methods to see which teachers have an impact on “non-cognitive” behaviors. One would expect – at least, I expected – that the teachers who raise test scores also raise non-cognitive outcomes. Not so.
For all outcomes, Algebra teachers with higher test score value-added are associated with better non-test score outcomes, but the relationships are weak…This indicates that while teachers who raise test score may also be associated with better non-test-score outcomes, most of effects on non-test score outcomes are unrelated to effects on test scores. The results for cognitive ability are consistent with this…
Results for English teachers follow a similar pattern. English teacher effects on English test scores explain little of the estimated effects on non-test score outcomes…
Because variability in outcomes associated with individual teachers that is unexplained by test scores is not just noise, but is systematically associated with their ability to improve typically unmeasured non-cognitive skills, classifying teachers based on their test score value added will likely lead to large shares of excellent teachers being deemed poor and vice versa.
So teachers can have large effects on matters that are supposedly out of their hands. Suspensions, absence rates and GPA are functions of a student’s conscientiousness – or more generally, of his character. This study delivers another blow to the cop out lobby.
But it also presents a huge challenge to the proponents of test-based teacher policies. Read this line again: “classifying teachers based on their test score value added will likely lead to large shares of excellent teachers being deemed poor and vice versa.” This is not a trivial matter. Jackson shows that non-cognitive outcomes are more strongly correlated with life outcomes than are test scores – especially for students with limited cognitive ability. This paper cannot be ignored.
Hat Tip: Joanne Jacobs
[Edited to correct formatting error and typos]