It’s no surprise high- and low-rated teachers are all around

Top-rated teachers can be found in all sorts of schools from “the poorest corners of the Bronx” to “wealthy swaths of Manhattan,”  reported the New York Times when value-added data reports were released.

The teacher effectiveness gap is a myth, concluded Mike Petrilli.

It’s no surprise, responds Gotham Schools. Value-added measurements . . . control for differences in neighborhood, student makeup, and students’ past performance.

The adjustments mean that teachers are effectively ranked relative to other teachers of similar students. Teachers who teach similar students, then, are guaranteed to have a full range of scores, from high to low. And, unsurprisingly, teachers in the same school or neighborhood often teach similar students.

“I chuckled when I saw the first [Times story], since the headline pretty much has to be true: Effective and ineffective teachers will be found in all types of schools, given the way these measures are constructed,” said Sean Corcoran, a New York University economist who has studied the city’s Teacher Data Reports.

The ratings “cannot compare” teachers who work with different kinds of students in different kinds of schools, concludes Gotham Schools, citing Douglas Staiger, a Dartmouth College economist.

Gotham’s story makes his post “basically moot,” Petrilli writes. However, he also linked to a working paper showing value-added differences between teachers in high-poverty and low-poverty schools aren’t large.

High-poverty, high-minority schools usually employ more new teachers, who are learning on the job, and fewer math, physics and chemistry teachers who studied their subject in college.  And these schools’ students don’t have parents who can teach them at home or hire tutors if they fall behind.  They rely heavily on their classroom teachers.

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