When choosing which schools to close, city officials say they pick the worst of the worst. But new graduation data released today shows that the city doesn’t always follow its own criteria.

Earlier this year, Department of Education officials announced their intention to close 19 schools based on the schools’ abysmal graduation rates and low test scores. Many of the schools on the list were high schools where less than half of all students graduated and progress reports were dotted with Cs and Ds. But absent from that list was Washington Irving High School, which has the city’s lowest graduation rate among traditional high schools and the highest drop-out rate.

In January, the Panel for Education Policy voted to begin closing a school 16 blocks north of Irving: Norman Thomas High School. Washington Irving was spared. But a look at the school’s graduation numbers and progress reports shows that in some respects, Irving is performing more poorly than Thomas is.

Washington Irving once was one of the city’s behemoth schools: a grand building in the middle of Gramercy filled with students from Harlem and the Bronx. Like Norman Thomas, it serves a high number of students with learning disabilities and recent immigrants, many of whom don’t speak English. In the last three years, Norman Thomas received Ds on its report cards, while Washington Irving was given two F grades and a C. Most recently, Norman Thomas’ graduation rate has increased slightly to 43 percent, while Washington Irving’s has decreased to 39 percent.

Both schools are on the State Education Department’s list of 34 city schools that it wants to see replaced.

Throughout the school closing hearings, critics have charged that the schools the DOE wanted to close didn’t meet the department’s own criteria and that some were even improving. At a City Council hearing, Deputy Chancellor John White defended the department’s choices.

“This is not a random list; these are the lowest performers even considered among a set of schools where students are not achieving at acceptable levels,” White said.

Going by graduation and drop out data for the class of 2009, Washington Irving is the city’s lowest performer, not including transfer schools and schools that have already been closed based on similar data. It’s not the only struggling school the city has decided to keep open, but it stands out when compared to those that are being closed this year, such as Global Enterprise High School, which has a graduation rate of 53 percent and received two Cs and a B on its progress reports in the last three years.

But DOE spokesman Daniel Kanner said the department focused on other criteria when deciding to keep Irving open.

“We look at a variety of factors when determining which schools to target for phase out and the 19 schools that we proposed to be phased out demonstrated a long-standing inability to serve students well,” Kanner said. “We take different actions based on different circumstances.”

Unlike some other schools that were closed for poor grades and graduation rates, the DOE saw Washington Irving floundering and gave it a boost.

Rather than close the school after it received two F grades, the department assigned Washington Irving an executive principal, Bernardo Ascona, who was given a $25,000 bonus to improve the school’s academics. The DOE also began downsizing the school, which had over 2,500 students in 2006 and has about 1,400 this year, according to its website.

“We’ve seen the school move from an F to a C,” Kanner said. “We’ve seen significant increases in 9th grade credit accumulation. We have more work to do but we have taken action and we’ll continue to build on the progress that we see they’ve made over the last year.”

Washington Irving students  said they like the new principal, but with so many students cutting class (the attendance rate hovers around 70 percent), the school hadn’t improved.

“The principal is trying really hard, but the students aren’t helping him achieve what he wants to,” said Imane Saif, a sophomore.

Ascona did not respond to requests for comment.