Baltimore's scores on a rigorous national math and reading test were in the bottom third of large urban school districts across the country, though educators highlighted some progress in math and a promising trend of better-than-average results among some low-income black students.

Overall achievement was poor on the National Assessment of Educational Progress, a test Congress mandated be given to a sampling of students across the nation every two years. The results released Wednesday showed that the city's children in fourth and eighth grades are scoring better than those in Detroit, Washington and Cleveland but behind those in New York, Boston and Atlanta.

"If you look at the absolute numbers, the nature of the challenge is huge," Baltimore schools CEO Andrés Alonso said. He said the results show the "urgency of the work" to be done in the school system. But deeper in the data, Alonso and others also found some reason for optimism.

Baltimore students "compared very well with African-American students in other districts," said Michael Casserly, executive director of the Council of Great City Schools, a group that represents urban districts. "We want to see more progress. I remain convinced they are on the right track with their reforms."

NAEP, also called the Nation's Report Card, began in the late 1960s and is the longest-running national assessment of basic skills. In recent years, a group of urban school districts have allowed a larger sample of their students to be tested so that the results could be compared among districts with similar demographics. Alonso decided several years ago that Baltimore would join the other districts so that the city's progress could be charted against its peers.

This year's results showed that only 11 percent of fourth graders are considered proficient or advanced readers, and only 17 percent are proficient or advanced at math. Twelve percent of eighth graders were proficient or advanced in reading, and 13 percent ranked in those categories in math.

Those results come more than a decade after public schools in Baltimore undertook a systemwide reform, and illustrate that the city still lags behind statewide scores. According to NEAP data released earlier this year, 40 percent to 48 percent of Maryland students in math and reading are considered proficient or advanced.

Alonso points out that below the discouraging data lie some positive trends. Baltimore is doing as well as many school districts with low-income black students, who comprise more than 85 percent of the student population. When the white, Asian, and middle-income students are stripped out of the data, Baltimore's scores look better.

For instance, Alonso said when he compared low-income students who are African-American males in the city to students in that same demographic in the other 21 urban school districts, the city ranked eighth, ahead of Atlanta, Los Angeles and Chicago — cities that are considered to have had success with education reforms.

Casserly said that African-American students in Baltimore are performing "at levels higher than what you would expect statistically" and so more analysis should be done to understand what reforms in Baltimore could be replicated elsewhere.

Baltimore also made progress in fourth- and eighth-grade math since the test was last given in 2009.

The city's fourth graders made the third greatest improvement in math of the 21 urban districts. Alonso noted that those teachers are among the least experienced compared to other districts. "So, maybe we need to stop talking about the experience of our teachers … and about what's going on in the classroom," Alonso said.

Eighth graders made the fifth largest gains in math, although that improvement isn't considered statistically significant. Scores dropped in fourth-grade reading and stayed constant in eighth-grade reading.

NAEP is considered more difficult than the annual state tests, including the Maryland School Assessments, on which Baltimore students score far better.

Alonso said he agreed to join the other urban school districts in NEAP testing because he wanted to change the discussion among teachers and administrators from how to meet the targets of the No Child Left Behind law to what students in the city needed to learn. And he said he wants the system aims for a bar "much higher than the bar that has been set before us."

The Nation's Report Card has charted significant progress in school districts where the test has been given since 2003. Atlanta, for instance, has made some of the largest gains in both math and reading in both grades. Boston, Chicago, Charlotte and Washington also have made gains in some areas. In addition, the urban districts that take part have been improving at a faster rate than schools in the rest of the nation.

"It is clear that the nation's urban public schools are not only improving but are catching up," Casserly said.

Math scores rose in the urban districts in 2011, while reading scores were stagnant. The reason, educators believe, is that math is taught almost entirely at school while many of the skills needed to become a good reader are also taught at home.

The city has been more focused on improving math, including providing more training for teachers and a Saturday school for students who need extra help. "Reading is where we're going to have to show that we are ready for that kind of transformation in the classroom," Alonso said.

The NAEP results include a wealth of data apart from subject scores, including information on how often students read for pleasure. Surprisingly, fourth graders who were asked to read aloud frequently in school performed worse on the NAEP reading test than those who weren't often asked to do so. And 80 percent of students tested in Baltimore are reading aloud in class almost every day.