HOUSTON -

The Houston Independent School District is facing a lawsuit over the method it uses to evaluate teachers.

At issue is the district's use of the Educational Value Added Assessment System, or EVAAS. The seven teachers who filed suit on Thursday claim the system is flawed, ineffective and insulting.

A teacher's EVAAS score is based on a student's academic growth throughout the year and it relies heavily on how the students perform on standardized tests.

"I have given Houston ISD my notification I will not be returning," said Myla Van Duyn, a biology teacher at Davis High School. "Instead of focusing on how to best care for students, such as giving them decent food at lunch, the money is being siphoned by private companies who are benefiting by making up the story of bad students and bad teachers."

A teacher's EVAAS score is used by HISD to determine how they are evaluated, whether they receive bonuses and, in some cases, whether a teacher is terminated by the district.

"We contend that threatening a teacher with termination based on a low EVAAS score is akin to threatening a teacher because it rained on the day of their evaluation. It's that arbitrary," said Craig Dietz, an attorney representing the teacher.

Dr. Terry Grier, HISD's superintendent, told Local 2 he is not surprised by the lawsuit.

"I respectfully disagree with them," said Dr. Grier. "I think you ought to be held accountable as a teacher for how much kids learn."

The lawsuit, filed in federal court on Thursday, contends that the teacher's constitutional rights to due process are being violated.

The suit also claims the process makes it difficult for a teacher to challenge the results of their evaluation.

"It's like a star-chamber procedure where the teacher literally has evidence brought against them they can't understand or they can't defend against," said Dietz.

No trial date has been set in the teachers' case.