The district still lags far behind the national average on the “Nation’s Report Card” from the Education Department.

Tough new teacher evaluations led to a strike this month in Chicago, but in the District of Columbia, such evaluations are “business as usual.”

Comprehensive teacher evaluations that take into account student performance are a central part of President Barack Obama’s education policy and of the national school reform movement. They also were a major point of contention in the seven-day long Chicago teachers’ strike, which ended Tuesday, September 18th.

In Washington, evaluations based in part on standardized tests have been used since 2009 to rate teacher performance, putting the city at the forefront of major school systems that are working to reform their personnel practices. All told, nearly 400 teachers have lost their jobs since the new evaluations were put into place.

The latest round of firings occurred last month, when 98 Washington teachers lost their jobs after a rigorous evaluation system found they weren’t up to snuff. The firings attracted no national media attention and little outcry locally. In fact, the president of the teachers union praised the school system for softening some of the evaluation criteria.

“It was a goal of mine to get to a point where this is business as usual,” schools chancellor Kaya Henderson said. “Any well-functioning organization fires people for performance, and that’s going to be a regular occurrence. Every high-performing organization also recognizes and rewards the highest achievers, and that’s now a regular occurrence.”

Henderson and other reform advocates say the new emphasis on teacher performance has markedly improved the quality of teaching in the district. But critics say the constant turnover has created an atmosphere of instability that drives away good teachers and doesn’t help students. They point to federal testing data that shows at best modest improvement in recent years.

“We have gone from a system where almost no one was terminated, no matter how bad, to the other extreme, where good teachers as well as bad are terminated,” said Mary Levy, an attorney and a longtime analyst of city education policy. “The latter is probably more damaging due to the stress and demoralization it causes.”

Washington was uniquely positioned to lead the charge on firing low-performing teachers. An act of Congress in the 1990s permitted the district to tie evaluations to test scores, but it wasn’t until then-Mayor Adrian Fenty took control of the school system in 2007 and installed Michelle Rhee as chancellor that school officials began to exercise that option.

Rhee fired nearly 1,000 teachers in her 3 years as chancellor, and some of the firings provoked legal challenges. She was known for inflammatory statements, including a magazine interview in which she said she laid off teachers “who had hit children, who had had sex with children.” She later clarified that two of the fired teachers had been accused of sexual misconduct.

The 2010 mayoral election was seen by many as a referendum on Rhee, and Vincent Gray defeated Fenty in the Democratic primary with strong backing from the teachers union. Rhee stepped down shortly thereafter.

Gray pledged to continue Rhee’s reforms with a more conciliatory, inclusive approach, and he appointed her deputy, Henderson, as chancellor.