AUGUSTA — A proposed statewide standard for evaluating Maine teachers’ performance puts too much importance on how students score on standardized tests, teachers told state education officials Monday.

“As teachers, we are asking to be evaluated on our performance, not our students’,” Kate Sheldon, an elementary teacher in Kittery, said at a public comment hearing. “There are so many factors that affect student achievement that are outside our control. There is also no fair way to gauge which specific teacher deserves the credit for gains, or the punishment for falling behind.”

Under the draft proposal, 25 percent of a teacher’s evaluation would be based on students’ performance on a standardized test. The Maine Education Association, which represents public school teachers, proposed Monday that the percentage should be no more than 10 percent of a teacher’s evaluation.

Much is riding on the new statewide standard, since it includes a provision that teachers who receive the lowest rating for two years can be dismissed.

“The possibility of creating a system that only paves the way for carte blanche nonrenewal of teachers is a very real possibility,” MEA President Lois Kilby-Chesley told the two Education Department staff members who heard the testimony. “The system should be designed to primarily offer opportunities for improvement and secondarily provide a mechanism for removal of ineffective teachers and principals.”

This is the first time Maine has tried to establish a common standard to evaluate teachers and principals. The Legislature passed a law last year requiring the system be in effect by the 2014-15 school year.

A task force that created the evaluation system did not reach agreement on what percentage of an evaluation should rely on student scores. The 25 percent figure was set by the Department of Education after the task force submitted its draft report late last year.

The task force did suggest how to measure students’ learning and growth, and what to disregard. For example, evaluators should consider only the statistically reliable test results, which may require three to five years of data.

The group also agreed the evaluation should not be based on certain other measures, such as student, parent and community surveys or high school graduation rates.

Other areas of concern raised Monday include:

* Privacy. As written, a teachers’ effectiveness rating in the form of a number would be public information. The MEA and several teachers said that should be confidential information.

* Cost. Kilby-Chesley said the MEA estimates it would cost $20 million in first-year start-up costs, and $10 million a year annually to cover training, time and paperwork to evaluate all teachers statewide every year.

* Specialty teachers. Several teachers noted that many instructors who must be evaluated don’t see students every day — such as language, art and physical education teachers — and others have students who don’t take or perform well on standardized tests, such as special education students. They questioned how those teachers would be evaluated.

* Evaluators. The proposal has fellow teachers performing evaluations, but some teachers questioned how familiar an evaluator would be on a particular topic.

* Union representation. The MEA suggested adding language in several sections to include representatives of the MEA.

Sheldon also spoke at length about the intangible efforts teachers make that cannot be captured in an evaluation, such as spending their own time and money to buy supplies, or making personal connections with students.

“How can it measure the extra time we pour into students who struggle to meet standards, due to devastating home situations? Well, the simple answer is that no system can do that,” Sheldon said.

No one spoke on behalf of the Education Department or in defense of some of the proposed rules, because the hearing was intended to be solely a forum for feedback. The proposal will now go before the Education Committee, whose members will make a recommendation to the Legislature, which must approve the proposal.

Setting common standards to evaluate teachers is a priority nationwide, and part of the federal No Child Left Behind Act. The federal government required states to establish standards to qualify for federal Race to the Top money.