Testing and Teachers

Republicans in the Indiana House of Representatives are taking action to remove test scores from teacher evaluations, the Indianapolis Star reports.


A bill to remove student test scores from performance evaluations that can impact teachers’ pay and promotion prospects unanimously passed a key committee Tuesday. Statehouse leadership is championing House Bill 1002, which could end up being one of the most consequential bills of the 2020 legislative session.


Current state law requires that test scores makeup a significant portion of a teacher’s evaluation, which rates them as highly effective, effective, improvement necessary or ineffective. A teacher’s rating can determine their salary, whether or not they’re eligible for raises or bonuses and impact their movement through the profession.

If this legislation is successful, Indiana will join states like Hawaii, Oklahoma, and New York in moving away from using testing — and, especially, value-added modeling — to evaluate teachers.

A study I reported on last year noted that using value-added modeling (as Tennessee does by way of TVAAS) is highly problematic. In fact, this particular study noted that value-added models suggest that your child’s teacher could impact their future height:


We find the standard deviation of teacher effects on height is nearly as large as that for math and reading achievement, raising obvious questions about validity. Subsequent analysis finds these “effects” are largely spurious variation (noise), rather than bias resulting from sorting on unobserved factors related to achievement. Given the difficulty of differentiating signal from noise in real-world teacher effect estimates, this paper serves as a cautionary tale for their use in practice.

In short, value-added data doesn’t tell us much about teacher performance. Additional data indicates further problems with value-added modeling for teacher evaluation — especially as it relates to middle school teachers:


Well, it could mean that Tennessee’s 6th and 7th grade ELA teachers are the worst in the state. Or, it could mean that math teachers in Tennessee are better teachers than ELA teachers. Or, it could mean that 8th grade ELA teachers are rock stars.


Alternatively, one might suspect that the results of Holloway-Libell’s analysis suggest both grade level and subject matter bias in TVAAS.


In short, TVAAS is an unreliable predictor of teacher performance. Or, teaching 6th and 7th grade students reading is really hard.

The study cited above showed that 6th and 7th grade ELA teachers consistently received lower TVAAS scores and that this was true across various districts. Or, as I noted: The study suggests both grade level and subject matter bias in TVAAS results.

Or, maybe, if your kid gets the “right” teacher, s/he WILL end up taller?!

The bottom line: Using value-added modeling to evaluate teachers is total crap.

Indiana’s lawmakers are finally catching on. It’s time for Tennessee to catch up.

For more on education politics and policy in Tennessee, follow @TNEdReport

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