When economists view schools simply through the prism of an algorithm, it is easy to remain oblivious to schools' complexity and diversity.
Eric Hanushek in "Waiting for 'Superman': How We Can Save America’s Failing Public Schools," made a big deal about the findings that teachers' value-added vary more within schools than across schools, as if that sound bite said anything about the quality of teaching in those schools. On the other hand,
“Getting Teacher Evaluations Right,” by Linda Darling Hammond, Audrey Amrein-Beardsly, Edward Haertal, and Jess Rothstein showed that Houston’s value-added models are especially unfair for teachers with large concentrations of English Language Learners (ELL) and/or special education
