Offering a blunt assessment of the state's failure to get rid of struggling teachers, Gov. Chris Gregoire on Tuesday proposed a tougher statewide evaluation system aimed at weeding out ineffective educators.

"The current system doesn't work," Gregoire said of teacher and principal ratings. "It's too broad. It doesn't help people grow. Teachers need to know what they're doing well, and where they can improve."

But union officials at one school district cautioned that new teacher evaluations are complex and difficult to implement, and that a statewide overhaul of educator evaluations by the 2013-14 school year is unrealistic.

When it comes to teacher evaluations, "the devil will be in the details," said Chris Korsmo, chief executive officer of the League of Education Voters, a public-policy group. "These tools are only as good as the folks using them."

In a news conference in Olympia, Gregoire described the new evaluations as part of a package of education reforms she is proposing to the Legislature.

They include a plan to create "lab schools" linked to universities at some of the worst-performing schools, and the formation of a new office that would help coordinate between high school and higher education so that students who graduate from high school are ready for college or other postsecondary training.

Gregoire linked the plan to her proposal to raise the sales tax by a half-cent; most of the money would go to education, offsetting budget cuts.

"I want voters to know what they're buying; they're making a good investment in an education system that's improving," she said.

Nationally, teacher-performance evaluations have been a hot education-overhaul item, with states and districts across the country moving to implement them.

An education-overhaul bill passed by the Legislature last year called for new teacher evaluations to begin in 2013-14, and the bill set aside money for 17 school districts — most of them small — to pilot a system of teacher/principal evaluations. Some other districts — including Seattle — have already created their own versions.

Gregoire's teacher/principal evaluations are more specific than the current law. They use four performance ratings: unsatisfactory, basic, proficient and distinguished.

Currently, in many districts, teachers and principals are only rated satisfactory or unsatisfactory. And although the 2010 law specified that all districts should have four tiers by 2013, it did not name and describe them.

Under Gregoire's proposal, teachers rated unsatisfactory would be placed on probation for a year. "You have that academic year to put it together, and if you don't, you're out — this is not your calling," Gregoire said.

Likewise, experienced teachers who are rated as basic for two consecutive years — or for two years in a three-year period — would also be placed on probation, and would be fired if they don't improve.

"If you are an experienced teacher, we should expect more than a basic level of performance," said Judy Hartmann, Gregoire's K-12 policy adviser.

The Snohomish School District began working on a teacher-evaluation plan in 2003, then joined the state's pilot program to develop evaluations last year. Careful evaluations "provide teachers with much more meaningful feedback about where they are," said Justin Fox-Bailey, president of the Snohomish Education Association.

But developing the evaluations has been a long, slow process, he said, and implementing them statewide by 2012-13 is unrealistic. "This is a big change, and you really want to do it well," Fox-Bailey said. "I'd be very concerned about districts that haven't started this at all."

One of the complexities of the pilot program's evaluation system is that teachers are evaluated on eight different criteria. If a teacher is rated unsatisfactory on one criteria but is meeting the standard or even proficient in the others, Fox-Bailey said, would that teacher be put on probation?

Snohomish has worked to make sure that a teacher's rating depends on clearly articulated standards, and isn't influenced by the evaluator, or the quality of the school where they are teaching, Fox-Bailey said.

"The learning curve is steep," he said. "To do it well, you really have to get into these issues. It's hard — it should be hard."

State schools Superintendent Randy Dorn said he was also proposing a new evaluation plan that would give unsatisfactory teachers a year to shape up or be fired; he said he would introduce a bill by the end of the week.

Dorn said he had not seen the details of Gregoire's proposal. Under current law, he said, a teacher rated unsatisfactory can be removed in a 60-day period, but the firing almost always results in a 2 ½ year court battle and costs the district about $100,000. "I'm not sure if her proposal is any different from that," Dorn said.

Washington Education Association President Mary Lindquist said teachers involved in the pilot of the evaluation system are "wholeheartedly enthusiastic" about it. But she also said she thought Gregoire's proposals were a distraction from the biggest issue — that the state is chronically underfunding its schools.

Katherine Long: 206-464-2219 or klong@seattletimes.com. On Twitter @katherinelong.