Students in both grades fared worse than the national average - Philadelphia fourth graders' average score was 195, and the U.S. average was 220. Philadelphia eighth graders scored 247, and nationally, the average was 262.
The 2009 results mark the first time Philadelphia has participated in the country's "Trial Urban District Assessment" program, and so there's no way to compare students' progress over time.
The test was given to about 1,300 fourth and 1,300 eighth graders at about 90 schools citywide. The schools and students tested reflected the district's overall demographics, officials said.
In Philadelphia and the other cities, there were gaps in performance between white students and Hispanic and black students, and poor students and those who are not poor.
District officials said the number of city students who scored below basic in the reading test was "a concern." Sixty-one percent of fourth graders and 44 percent of eighth graders scored below basic.
"Since the time students took the exam in early 2009, the district has implemented targeted interventions in our high-needs schools, rather than employing multiple sources of interventions," a spokesman said in a release.
The district is also redesigning its core curriculum, focusing on early reading in high-needs schools.
Michael Schlesinger, the district's deputy for assessment, said that officials "look at this as a baseline, anxious, of course, to see how we do in two years. I think if interventions are implemented well, we will see increases down the line."
The NAEP is different than the Pennsylvania Standard of School Assessment (PSSA), the state test given annually. The NAEP is considered "the gold standard of educational assessments," Schlesinger said, more rigorous than most state tests.
PSSA scores have risen for seven consecutive years. But that progress has been incremental, and about half of all students still cannot read or do math on grade level.
Contact staff writer Kristen Graham at 215-854-5146 or email@example.com.