Comment of using growth scores for all students to measure school performance. Posted at npr.org.
Prof. Morgan Polikoff suggests that we no longer use “percentage of students rated as proficient” to hold schools accountable.
Polikoff's proposal is to use growth of all students as a measure of achievement.
This plan still relies on standardized test scores to define achievement, which encourages gaming the test via test preparation. This is like claiming you have raised the temperature of the room but all you have done is light a match under the thermometer.
Also, relying on growth is a big problem. You can't just compare end of year test scores, because of the powerful influence of summer: We have known since 1975 that middle class children improve during the summer because they have more access to books. This means we would need to test in the fall and again in the spring, which doubles the amount of testing, increasing the already unacceptable amount of testing students endure.
Heyns, Barbara. 1975. Summer Learning and the Effect of School. New York: Academic Press.
Original article and comments: http://www.npr.org/sections/ed/2016/07/18/486196906/here-s-an-idea-ask-experts-how-to-rate-schools
Polikoff letter to US Dept of Education: https://morganpolikoff.com/2016/07/12/a-letter-to-the-u-s-department-of-education/