UPDATE 4:05 p.m. This item has been updated to reflect a new count of the total number of teachers fired for poor ratings--206, not 227. Also, the tally of teachers fired in 2010 for poor ratings is now given as 75, not 126.

The District fired 206 teachers for poor performance Friday, the second year in a row it has dismissed significant numbers of educators for sub-par work in the classroom.

Those fired amount to 5 percent of the 4,100 teachers in the city school system.

They were dismissed for poor scores on the evaluation system known as IMPACT, which grades teachers on five 30-minute classroom observations and their compliance with nine broad standards. These include ability to express course content clearly, teach students with differing skill levels and manage time effectively. For some teachers, half of their appraisal is contingent on whether students meet predicted growth targets on standardized tests.

The evaluation system, one of the nation’s most rigorous and closely watched, is a legacy of Michelle A. Rhee’s tenure as city schools chancellor. Rhee, who resigned in October, was succeeded by her deputy, Kaya Henderson.

Of the 206 fired, officials said 65 were rated ineffective this year and 141 were judged minimally effective for the second consecutive year. Others were let go for licensure problems or other issues.

Four teachers who were rated minimally effective two years in a row received waivers from Henderson, enabling them to continue to teach in the city, based on the recommendation of principals who said they still had potential for improvement.

Another 663 teachers (16 percent) were rated highly effective, making them eligible for performance bonuses of up to $25,000. The vast majority were rated effective.

Last year, IMPACT’s first in operation, 75 teachers were let go for poor scores.

“Great teachers are critical to our success,” Henderson said in a statement. “We are delighted to be able to shine a spotlight on our top performers. We also remain committed to moving out our lowest performers in an effort to ensure that every child has access to an outstanding education.”

Large-scale dismissals of teachers for job performance is still a rarity in big city schools, experts say. Collective bargaining agreements and often-cumbersome appeals processes, combined with a reluctance on the part of officials to confront politically potent unions, have limited firings.

“The only people who typically lose their jobs in districts are people who are guilty of a crime,” said Kate Walsh, president of the National Council on Teacher Quality, an organization that studies and promotes methods to improve instruction in schools. “It’s rare that there are any significant numbers of teachers who lose their jobs because they are not good at teaching their subjects.”

D.C. public schools and other school systems have had annual evaluation systems for many years. But they have typically been pro forma affairs, with the overwhelming majority of educators receiving satisfactory ratings.

Rhee, citing research that showed teacher quality is the largest in-school factor driving academic growth, revamped evaluations. Her effort was buoyed by an unusual feature of District law, which unlike many other cities, exempts evaluation systems from collective bargaining. That meant Rhee enjoyed broad latitude in designing IMPACT.

Union leaders and many teachers have assailed the system as arbitrary and punitive. They call it a vehicle for Rhee, and now Henderson, to push older veterans out of the system. They assert that IMPACT does little to help develop them professionally and makes little allowance for school or classroom conditions that hinder instruction and lead to lower evaluation ratings. Union leaders are fighting IMPACT in the courtroom and in discussions with Henderson and members of the D.C. Council.

In the 2009-10 school year, when IMPACT debuted, almost 70 percent of teachers (2,892) scored in the “effective” range. About 16 percent (663) were rated “highly effective,” making them eligible for performance bonuses of up to $25,000. Less than 2 percent (72) were deemed “ineffective” and dismissed. Another 13 percent (568) were found to be ”minimally effective.” Of those, a small number had their jobs eliminated last year for budget or enrollment reasons. The rest are subject to termination this month if they receive the same rating.

More on D.C. Public Schools:
How we determined the number of teacher firings

Henderson relaxes rules for some veteran teachers

D.C. CAS scores worse than projected, but who’s counting?

From January: Profile of Kaya Henderson