Attendees at the GradNation Summit listen to a speaker before New York City Mayor Michael Bloomberg addressed the audience. (Tom Meyer/ Medill)

WASHINGTON — New York City Mayor Michael Bloomberg, a long-time advocate of education reform, called Tuesday for a  strong focus on reducing absenteeism in schools and advancing graduation from high school.

Bloomberg urged school districts to concentrate on keeping kids in school.

“We still have a lot more work to do to ensure kids finish school, and that starts with reducing chronic absenteeism in schools,” Bloomberg said. “It’s a national problem.”

Bloomberg spoke via video at the Building a Grad Nation Summit, an annual conference sponsored by America’s Promise Alliance, a Washington-based nonprofit that advocates for children and youth. The conference has a stated goal of achieving a 90 percent high school graduation rate by 2020, which Bloomberg supports.

“Tragically, truancy numbers are the highest for low-income students, for whom an education is the best route out of poverty,” he said. “We have to commit to do more, as we have in New York.”

Bloomberg has been mayor of New York since 2002, and has used his vast personal fortune to promote gun control and climate change legislation nationally.  But he did not commit to using his political action committee funds or personal wealth to back the effort, as he has in promoting gun control.

He was mentioned as a possible presidential or vice presidential candidate in 2008 and endorsed President Barack Obama’s reelection late in the 2012 campaign.

He touted efforts that he said have helped the city’s troubled schools during his 11 years as mayor.

“Improving public schools has been one of my administration’s highest priorities and we’ve had a lot of success,” Bloomberg said. “We’ve raised high school graduation rates, up 41 percent since 2005, and our college acceptance rate has doubled.”

New York City’s graduation rate rose to 65 percent in 2011, the latest year for which data was available. Nationally, however, the high school graduation rate has been steady at 78 percent. The graduation rate is significantly lower among African-Americans and Hispanics, with only 66 percent and 71 percent, respectively, graduating.

“We need to highlight innovative programs to help students before they drop out, and focus on mentoring and monitoring absenteeism in our schools,” Bloomberg said.