Colorado teacher evaluations would be less tied to test scores under a bill introduced this week, but the changes are more limited than in earlier drafts of the proposal.

Most notably, the bill does not call for experienced teachers with effective ratings to get a formal evaluation just once every three years, instead of every year as current law requires.

The Colorado Education Association, the state’s largest teachers union, had made changes to the teacher evaluation process one of its top legislative priorities, alongside more funding for schools. Colorado’s teacher effectiveness law, passed in 2010, was a key piece of that era’s education reform agenda, and many teachers consider it burdensome and unfair. In text messages and tweets, the union urged members to call legislators and demand changes to evaluation.

Some school administrators, particularly those from smaller rural districts, have also called for changes.

But a wide range of education advocacy groups raised concerns about the proposed changes, particularly the call to end “every teacher, every year.” The bill’s introduction was pushed back repeatedly as it was rewritten.

Senate Bill 247, sponsored by state Sen. Tammy Story, a Conifer Democrat, was introduced Tuesday, with a little less than three weeks left in the legislative session. It is scheduled to get its first hearing Thursday in the Senate Education Committee.

Story did not return a phone call seeking comment Wednesday.

The bill has two main provisions. It would reduce the portion of the evaluation tied to student growth from 50 percent to 30 percent, and it would convene a working group made up of the education commissioner, lawmakers, parents, students, and educators to study how the teacher effectiveness law is working now and recommend changes by November.

Amie Baca-Oehlert, president of the state teachers union, said this new version of the bill does not represent a union retreat.

“For us, going to [the working group] is not a move away from [changing] ‘every teacher, every year,’ but that there were other things that needed to be looked at,” she said. “What has been most important for us this session is that educator voice be elevated and included in conversation, and that’s the most important thing to highlight in this bill.”

Baca-Oehlert said there seemed to be “broad resonance” that student growth should not account for 50 percent of a teacher’s evaluation. In interviews earlier this year, state education officials and advocates for more accountability said they were open to having that discussion.

Researchers disagree about how much and whether it’s fair to tie teacher ratings to test scores, which are affected by many factors, and many states are moving away from basing teacher evaluations on test scores.

Current law says that a teacher evaluation should be based 50 percent on student growth and 50 percent on professional practice. Districts can use a variety of factors, not just test scores, to measure student growth, but in practice, test scores are often used to evaluate teachers whose subjects aren’t even included in standardized tests, with each teacher carrying some responsibility for the outcomes of the school as a whole.

State education officials say that districts have the flexibility to change how they measure student growth, and the law does not need to change to address many teacher concerns.

The bill calls for 50 percent of a teacher’s evaluation to be based on professional practice, 30 percent on student growth, and 20 percent on factors determined by local school boards. It also states that the standards for measuring effectiveness must include factors such as student engagement, student behavior, attendance, and attainment of goals in individualized plans for students with disabilities or who are gifted.

Luke Ragland of the conservative education advocacy group Ready Colorado, said that’s a problem for him.

“Any time you see a reduction in the value we’re placing on student outcomes, that’s concerning,” he said. This change won’t make evaluations more meaningful or less burdensome, he added. “It simply devalues student outcomes.”

Ragland said he’s also concerned about how the membership of the working group is described in statute. The bill says that certain teachers and administrators should be selected based on the “advice of a statewide association” that represents teachers, school executives, and school board members respectively. That gives more influence to the institutional voices, he said.

“I think this is set up to be a one-way street with predetermined outcomes,” he said. “I don’t see this as a real conversation about how to improve.”

In addition to keeping the frequency of teacher evaluations unchanged, the bill leaves in place rules about how teachers earn tenure or “non-probationary status,” which affords them some job protections, and the controversial provision that allows non-probationary teachers to be put on unpaid leave if they’re laid off and fail to get re-hired by a principal within a set amount of time.