NASHVILLE, Tenn. – Tennessee’s public schools are already reaping benefits from the state’s new teacher evaluation system.

According to Nashville Public Radio, “Public school teachers with the lowest scores in a new evaluation system appear more likely to retire.”

Data from the Tennessee Department of Education shows that “nearly four percent of retiring teachers have the worst-possible scores,” while less than two percent of outgoing educators rank among the highest achievers, reports WPLN.org.

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These developments seem directly linked to a 2010 Tennessee law which linked a portion of a teacher’s annual job performance rating to student achievement, as measured by standardized test scores.

That is a marked contrast to the casual way a teacher’s performance used to be measured in the Volunteer State.

“Under the old Tennessee system, tenured teachers were evaluated just twice a decade,” wrote U.S. Education Secretary Arne Duncan in a Huffington Post column last year. “A teacher’s impact on student growth did not factor at all into their performance evaluation. Not surprisingly, virtually all teachers received positive ratings.”

But now Tennessee’s teachers are being held accountable for what their students are learning in their classrooms.

Duncan noted that “50 percent of a teacher’s evaluation (is) based on student achievement data – 35 percent on student growth, with the other 15 percent based on other measures of student achievement. The remaining 50 percent of the evaluation would be based on traditional qualitative measures, like observations of teachers by their principals.”

Most Tennessee educators have little to worry about; the state is experiencing historic gains in student achievement since the 2010 law.

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But some teachers are worried. That is why a number of them are opting for an early retirement and heading for the exits.

Generally, ineffective teachers know who they are. They understand that they don’t have what it takes to manage a classroom of spirited students or to make the connections that are essential to learning.

They know they should find another career, and the new evaluation system is giving them that much-needed nudge to do so.

Nobody likes to see a decent, well-meaning person lose his or her job. But educating children is too important a task to leave to amateurs.

Tennessee’s new evaluation system may be tough, but it’s going to result in better teachers in Tennessee’s classrooms.

Apparently, it already is.