The new D.C. system is meant to reward teachers instead for their performance in the classroom, continuing a shift that began three years ago with evaluations that linked pay and job security to student performance on standardized tests.

Besides making bigger salaries, teachers who reach higher rungs will undergo progressively fewer classroom observations and will qualify for more — and more substantial — leadership positions within their schools and across the school system.

Schools Chancellor Kaya Henderson said the aim of the initiative is to entice excellent educators not just to come to the city, but to stay here and to stay in the classroom. Teacher turnover — a problem in almost all city school systems — is notoriously high in the District.

“Our goal is to be the highest-performing urban school district in this country,” the chancellor said, “and the only way we do that is to ensure that we are able to attract and keep the very best people.”

Henderson announced the initiative in a joint event Tuesday with Washington Teachers’ Union President Nathan A. Saunders, who endorsed the career ladder as “a good program” that will make the city a more attractive place to teach.

Mid-career teachers in particular, Saunders said, can make more money than was previously possible in the District and get raises faster than in neighboring school systems.

In Fairfax, for example, a five-year veteran with a master’s degree makes $53,262. In the District, a teacher with equivalent experience who moves up the ladder with two highly effective ratings — or four effective ratings — can make almost one-third more, or $69,132.

The D.C. public school system has offered merit pay since 2009. Outside donors footed the bill for the first three years, but now that money has dried up. The school system has absorbed the costs, budgeted for $6 million next fiscal year, according to a spokeswoman.

The career ladder doesn’t change the pay ceiling, which is $131,540. But incentives have been tweaked so that the largest increases are reserved for teachers in schools where more than 60 percent of children qualify for free or reduced-price lunches, a federal measure of poverty.

Critics, meanwhile, continue to wonder whether evaluations based on test scores are a fair way to judge the complicated craft of teaching. “It’s a very simplistic notion of what it means to be a good teacher,” said Mark Simon, a longtime observer of D.C. public schools and former president of the Montgomery County teacher’s union.

There are five rungs on the career ladder. At the bottom is a “teacher,” who gets normal pay and four formal classroom observations each year.

Climbing the ladder requires earning “effective”and “highly effective” ratings on annual evaluations. An educator who reaches the top rung, an “expert teacher” — which requires at least six years’ experience — is subject to just one classroom observation a year. Experts also leap ahead in pay, receiving the salary of someone with five more years’ experience and a doctorate.

Expert teachers are also eligible for the broadest array of leadership positions, including assistant principal, curriculum specialist or instructional coach.

All of the city’s approximately 4,000 teachers have been placed on the ladder based on their evaluation scores over the past three years. A quarter are on the bottom rung. Half are “established,” the second rung. Fifteen percent are “advanced,” the third rung, and 10 percent are “distinguished,” the fourth rung.

No one is at the top yet because there isn’t enough evaluation data; the earliest anyone will be able to reach “expert” is the 2014-15 school year.

Teachers cannot move downward on the ladder. That’s meant to lend more stability than was available under the previous system, in which rewards hinged on annual evaluations that vary from year to year.

But even experts aren’t protected from losing their jobs if they have a year or two of weak evaluations.

“Nobody’s safe from IMPACT,” Saunders said, referring to the evaluation system that he has long criticized as arbitrary and overly punitive.

“Nobody’s safe from low performance, and that’s the way it should be,” Henderson replied.