D.C. Public Schools officials are making the first fundamental change to the teacher evaluation tool that many regard as the most controversial reform of the Michelle Rhee era, The Washington Examiner has learned.

Under Impact, teachers and other educators are observed at schools five times each year and scored on a scale of 1 to 4, or "highly effective." But this school year, the 290 teachers who received "highly effective" ratings for the past two years and who earn an average of 3.5 on their first two evaluations this fall will have the option to waive the three remaining observations.

"This is something we've been hearing from teachers and principals since Impact was launched," said Scott Thompson, director of teacher effectiveness strategy for DCPS. "Everyone thinks it's reasonable to be evaluated and held to high standards, and if [teachers] consistently demonstrate they are high-performing, it didn't seem like they needed to be observed quite as many times."

One observation will be conducted by an independent "master educator," while a school-based administrator -- often a principal -- will oversee the other.

Thompson said the new option will be tested this year; if teachers who waive three evaluations don't score as well next year, DCPS will have to figure out what options are available then. The opt-out option is also available to other educators, including social workers and custodians.

Washington Teachers' Union President Nathan Saunders said he would "like to take credit" for the change, which he believes the 4,100 teachers he represents will receive well.

Saunders has fought DCPS in court to crush parts of Impact and overturn the firings of hundreds of DCPS teachers for poor evaluations in the past two years.

Classroom observations are the largest chunk of Impact ratings, 75 percent, for teachers in most grades. For those who teach classes tested on D.C.'s standardized tests, observations count for 35 percent; the biggest piece is the 50 percent resting on students' test scores, where more scrutiny has fallen -- including local and federal investigations into cheating by teachers.

"Now, we move on to higher fruit on the trees, with regard to Impact," said Saunders, who would like to see more professional development for teachers.

Highly effective teachers have been offered salary increases up to $20,000 and lavish annual bonuses under Impact, funded by private donors solicited by Rhee.

Ashley Allen, a partner at Endeavor Group, a firm that advises philanthropies on local education donations and a member of Horace Mann Elementary's PTA, said she thinks donors will generally support fewer evaluations for top teachers.

"Philanthropies are philosophically in favor of taking what's proven to work, and giving it flexibility and autonomy," she said.

While she supported the change, Allen said the plan had drawbacks. "You have teachers who are right on the line of 'highly effective' who would benefit from more feedback, so if they opt out of the observations, it could shortchange them," she said.

DCPS has been planning the tweak for at least a month. Speaking on a panel following a documentary screening on Aug. 4, Woodrow Wilson Senior High School teacher Angela Benjamin -- who falls in the select 290 -- said she had asked Chancellor Kaya Henderson to consider observing her fewer times.

Cate Swinburn, executive director of the D.C. Public Education Fund, which solicits private donations to fund Impact, told the audience that it was in the works, "and honestly, I think it's going to happen," she said.