Rachel Klein, the education editor of Huffington Post, reports on a recent study by Mathematica Policy Research that found that teachers and low-income and in upper-income schools are no different in effectiveness.

This study is very important because a central tenet of the corporate reform movement is that “bad teachers” cause low test scores, and that low-scoring schools are overrun by “bad teachers.” We have heard this claim from the mouths of Bill Gates, Arne Duncan, Michelle Rhee, Joel Klein, and every other corporate reformer. This is why Race to the Top required every state applying for a share of $4.35 billion in federal funds had to agree to evaluate teachers based in large part on the test scores of their students. Think tanks, states, and the U.S. Department of Education have poured time and energy into the pursuit of the best way to find and fire those “bad teachers.” Another of Arne Duncan’s bad ideas was the “turnaround” model, which involved firing half, or most, or all of the school staff, since in his mind the staff caused low scores.

The study used the “reformers'” favorite methodology–value-added measurement–to look for differences in teacher effectiveness.

Klein writes:

Teachers shouldn’t be held responsible for the big gap in the achievement levels of rich and poor students, new data suggests.

By looking at the effectiveness ratings of teachers who work with students from varying socioeconomic classes, Mathematica Policy Research determined that rich and poor children generally have access to equally impressive educators. The research, which was sponsored by the U.S. Department of Education, stands in the face of arguments that a more equitable distribution of teachers could substantially move metrics of educational attainment.

Affluent students outperform their low-income peers on meaningful educational benchmarks. They have higher high school graduation rates and higher standardized test scores. Policymakers have said in the past that teachers might influence this gap. Indeed, previous data shows that low-income students tend to have less access to experienced teachers.

“We know from past research that there is a very large gap in achievement between high- and low-income kids, and we also know some teachers are quite a bit more effective than others,” said Eric Isenberg, senior researcher for Mathematica. “So we were interested in exploring whether there’s a link between those two things ― if achievement gaps could be explained by low-income kids having less effective teacher than high income kids.” .

The study looked at effectiveness ratings for English language arts and math teachers in 26 districts over the course of five years. These teachers worked with students in the fourth through eighth grades.

Researchers used a value-added model to measure the effectiveness of a teacher. This statistical model is controversial in the education world ― Isenberg called it an “imperfect measure,” but he said it’s the best available option. This statistical technique is used to isolate how students’ test scores change from year to year, and how much a teacher is contributing to these changes.

Although researchers did not work with a nationally representative sample of school districts, “the study districts were chosen to be geographically diverse, with at least three districts from each of the four U.S. Census regions,” the report says. About 63 percent of the students in the studied districts qualify for free or reduced-price lunch, and the districts’ achievement gaps tend to reflect those at the national level.

Overall, researchers only found small differences in the average effectiveness ratings given to teachers working with low-income and affluent students. The average teacher of a low-income student rates around the 50th percentile, while the average teacher of a more wealthy student rates around the 51st percentile.

As Linda Darling-Hammond once wrote: “You can’t fire your way to Finland.”

In Finland, teaching is a highly prestigious profession. Entry into teachers’ colleges is very competitive. Teachers must have five years of education before they can teach. Once they are professionals, they have broad autonomy, and they collaborate with their peers to make school wide decisions. There is no standardized testing until the end of high school. There is an emphasis on the arts, play, technology, and collaborate learning. Children have a recess after every class. Teachers are professionals. They are not judged by test scores because there are no test scores.

The policies of the Bush-Obama era have failed and failed and failed. It is time to think anew.