Facing simmering opposition, the State Education Department seems likely to give up on a plan to add more weight to test scores in teacher evaluations.

Education officials have long intended to increase the percentage for which test scores count toward a teacher’s overall evaluation by 5 points, from 20 to 25 percent. A provision in the state’s evaluation law, passed in 2010, allows for the increase if officials adopt a more complex “value-added” model to measure student growth.

Commissioner John King always planned to embrace the option, but his proposal at April’s Board of Regents meeting was met with resistance from members who questioned the methodology’s reliability and asked to shelve the plan. In recent weeks, the state teachers union also lobbied members who were on the fence.

This week, Chancellor Merryl Tisch signaled the pressure was effective, acknowledging that she expected the Board of Regenst to hold off on the proposal when it meets next week.

“This is not the stuff that I feel we go to war over,” Tisch said Monday in a radio interview.

King and Tisch have repeatedly declined calls to slow down implementation for the major parts of their reforms on standards, testing and evaluations. The possibility of a concession comes just two days after thousands of teachers and advocates protested in Albany to rally against the state and country’s education policies.

Tisch struck a conciliatory note on Monday when explaining the state’s reasons for reconsidering.

“I think we’ve heard very carefully from teachers [and] principals about the need to go about this cautiously,” Tisch said.

“I think that the rally had to be on her mind when she spoke Monday morning,” said New York State United Teachers President Dick Iannuzzi, who added that union leadership had also been explaining their position to Regents last week.

Ianuzzi said that he wanted to minimize the weight of test scores because he isn’t confident that the state will be able to accurately calculate student growth that compare results from two different types of tests. Last year’s tests were based on state standards, but this year’s tests are based on new national standards known as the Common Core.

If the Regents decide not to introduce a value-added formula, some districts across the state could face paperwork headaches. Hundreds of districts will have to revise their evaluation plans to specify what they will do if there is no value-added measure, state officials have said.

But in New York City, there is no issue. Because the city’s evaluation system does not take effect until next year, city teachers would not get scores based on this year’s value-added data anyway.

Tisch said New York City’s implementation timeline could delay the introduction of value-added for the rest of the state. She said she was “mindful that the largest school district in the state is just going to start its evaluations system in September. So I wouldn’t be surprised if there was a lag time of a year or two.”

Even if the weight of test scores don’t increase, Tisch said she expected that some variables of the value-added model could still be used to measure student growth this year and next. The variables take into classroom characteristics, such as the ratio of high-needs students in a teacher’s class, and student demographic information, such as whether their families are in poverty.

“I don’t believe that necessarily we need to wait for valued added to add those critical indicators,” Tisch said.

State education officials declined to comment.