The Washington Teachers Union will file a class-action lawsuit on behalf of its 241 teachers fired last week for poor performance in the classroom, union President George Parker said Monday.

"The story is not the firings so much as the document upon which the firings are based," Parker said. "It is a flawed document."

He derided the "euphoric" reaction of observers and news reports nationwide, saying he's "never seen a superintendent receive less scrutiny than Chancellor [Michelle] Rhee."

"There's this sense that since [other superintendents] haven't been able to do something like this, she must be right," he said. "They assume that if she's firing people, they must be poor teachers."

The document in question is the D.C. Public Schools' teacher and staff evaluation tool, called Impact, which rates teachers from "highly effective" to "ineffective." An "ineffective" score left 185 of the system's 4,300 teachers without a job in the fall -- about 10 times the average number of firings in similarly sized districts. Another 56 teachers were let go for licensure problems.

Fired teachers can file grievances if the process of their evaluation was flawed -- for example, if they received only four observations instead of the required five. They cannot file grievances based on the outcome of the evaluations.

Rhee said her team intentionally did not fire teachers whose process they knew to be flubbed -- leaving the union with little room for remedy.

The class-action suit would address what Parker sees as the unfair pieces of the evaluation tool, developed by Rhee's central office team without union input. It will be filed as soon as D.C. Public Schools releases to the union a list of the fired teachers, he said.

Parker is especially miffed that 5 percent of a teacher's overall score is based on the performance of his or her school.

"A teacher's evaluation should be based on what he or she can control," he said.

He also condemned the speedy implementation of Impact, saying one year was not adequate for teachers and evaluators to fully understand the expectations. Parker pointed to a survey completed in the winter of about 1,000 union teachers who overwhelmingly disapproved of Impact. About 80 percent of those who returned surveys scored "effective" or "highly effective," Parker said.

"They would've had every reason to say this was a great document, and they didn't."

Jason Kamras, 2005 National Teacher of the Year and the DCPS official responsible for Impact's implementation, argued that the program offers one of the most comprehensive and high-quality evaluations in the country, and was developed with the input of nearly 1,000 teachers and principals. "It becomes the engine of change for the school system," he said.