Charter schools had to replace an average of more than half of their teachers between 2008 and 2010, a turnover rate on par with some of the most troubled district-run schools.

Experts say that high teacher turnover is associated with a school in turmoil and that instability often hampers student performance.

Of the 10 charter schools with the highest turnover, only one—LEARN Charter—had the majority of its students score at or above the state average on the ISAT.

Chicago’s charter teacher turnover—from an analysis of charter employee lists obtained by Catalyst Chicago—mirrors a nationwide trend.

California has been a hospitable state for charter schools, approving hundreds of them on the understanding that they would provide better educational options for students who were otherwise stuck in abysmal, unsafe schools, and that they would model innovative ideas for the public school system. And in many cases, that's precisely the way it has worked.

But there are steep variations in the quality of these schools, which are publicly funded but free from many state regulations. As a Stanford University study found last year, some do a better job than the public schools their students would have attended, some do worse, and a large number do about the same. The school districts that approve the charters often ignore mediocre performance when the time comes for reauthorization.

Chicago Math and Science Academy Also Challenges Teachers’ Union Rights

The Chicago Math and Science Academy (CMSA), a public charter school, fired a highly regarded pregnant teacher who helped organize a union at the school in June. The firing occurred as the school also challenged its teachers’ right to form a union.

The teacher, Rhonda Hartwell, was eight months pregnant at the time of her firing and was forced to move up her scheduled delivery to ensure it occurred before her health insurance was cut off.

“It’s one thing for the school to fight the union’s legitimacy, but it’s quite another to retaliate against a union organizer who has been rewarded with performance bonuses and was pregnant. This is about as low as an anti-union administration can go,” said Kim Bobo, executive director of Interfaith Worker Justice.

Civil rights leaders are criticizing Obama administration education reforms aimed at turning around low performing schools and closing the achievement gap for minority students.

Eight civil rights organizations, including the NAACP, contend in a document released Monday the Education Department is promoting ineffective approaches for failing schools. They also claim the $4.35 billion "Race to the Top" grant competition -- a program with a goal of spurring innovative reform in states -- leaves out many minority students.

Teachers at the highly regarded Chicago Math and Science Academy notified school leaders Wednesday that they have organized into a union and filed for recognition with the Illinois Educational Labor Relations Board to help make an already great school even better.

“Ensuring continued student and teacher success involves creating an environment in which teachers feel secure enough to raise concerns and offer ideas,” said Brian Chelmecki, chair of the school’s math department. “Chicago Math and Science Academy teachers need a strong voice in developing and implementing policies that are good for kids and fair to teachers.”