State Superintendent of Education Hanseul Kang unveils the D.C. School Report Card during a press conference Friday at Tubman Elementary School. (Bonnie Jo Mount/The Washington Post)

Half of the District’s lowest-performing schools are east of the Anacostia River, according to a rating system unveiled Friday that assigns the city’s schools one to five stars.

Five of the 10 D.C. public schools — traditional or charter — in the bottom 5 percent of ratings are in Ward 8, according to data released by the Office of the State Superintendent of Education. The superintendent’s office will divide $11 million in federal grant money among those 10 schools over the next three years in a bid to boost them, Superintendent of Education Hanseul Kang said.

Kang’s office previously sent improvement grant money to about 30 schools but will concentrate the money on the neediest schools in coming years.

“We know that this kind of significant and sustained investment is what it takes to help a school improve,” Kang said.

The 10 schools that will receive the grants were among 19 — 9 percent of schools overall — that received one-star ratings under the new system.

WASHINGTON, DC - DECEMBER 7: DC Public Charter School Board Executive Director Scott Pearson, reviews school ratings during a press conference announcing the DC School Report Card at Tubman Elementary School in Washington, DC on December 7, 2018. (Bonnie Jo Mount/The Washington Post)

Three-star ratings were awarded to 36 percent of schools. Seventeen schools boasted five-star ratings, according to the superintendent’s office.

Mayor Muriel E. Bowser (D) noted during a news conference at Tubman Elementary School in Columbia Heights that each of the District’s wards had schools that received four-star ratings.

“There are, across every ward, schools that are performing at a high level,” Bowser said. “If we know that we have schools that are challenged and need interventions, this gives us a common framework to be able to discuss those challenges and interventions.”

Charter schools fared slightly better on the star rating system than the city’s traditional public schools: 67 percent of charters and 60 percent of the city’s traditional public schools were issued a three-star rating or higher.

Amanda Alexander, interim chancellor of D.C. Public Schools, said her office plans to work with administrators at the lowest-performing schools to identify resources they may need.

“Each school is unique,” Alexander said. “Each school has its own context, its own strengths and weaknesses. We want to work really close with them.”

Scott Pearson, executive director of the D.C. Public Charter School Board, noted that just five charter schools received one-star rankings. Three of those schools, he said, are being reviewed by the Charter School Board this year.

“Each of those schools, as independent public charter schools, needs to chart its own course for improvement,” he said.

District education officials developed the rating system after the Barack Obama administration’s 2015 Every Student Succeeds Act mandated that states and the District create uniform and easily accessible report cards for schools by the end of this year. The federal law requires that certain data, including standardized test scores and graduation rates, factor prominently into the measurements.

In the District, standardized test scores — and whether they are improving — account for 70 percent of elementary and middle school rankings. For high schools, test scores are responsible for about 40 percent of the rating.

The rankings also reflect how effectively schools educate students from underserved populations, including English-language learners. It also considers the percentage of students who re-enroll in the school and participation and performance in Advanced Placement classes and on AP exams.

State education officials scored schools by using a numerical scale on which schools could receive up to 100 points. That was then converted into a star rating.

The highest-scoring school was Benjamin Banneker High in Northwest, which received 99 points. The lowest-scoring school was Anacostia High in Southeast, which received about 3 points.

Critics have argued that the District’s emphasis on test scores will result in the highest marks going to schools that teach the wealthiest students and saddle schools that teach the neediest children with the worst ratings, even if the schools are improving.

Scott Goldstein, executive director of EmpowerEd DC, a teacher advocacy group, said he is worried that the star ratings will exacerbate inequalities and punish schools with more students considered at risk — defined as those who are homeless, receive welfare or food stamps, or have struggled in high school.

Parents, he said, may overlook schools with a lot to offer because they are poorly rated. For example, Roosevelt High School, where Goldstein once taught, provides a dual-language program and offers arts, extracurricular and vocational opportunities that he said many parents may seek.

He encouraged parents to visit a school and explore whether teachers and the principal return to their posts year after year — stability in leadership, he said, can point to growth.

“My fear is that parents are going to look at those scores and perhaps ignore those schools,” Goldstein said.

The rating system is one aspect of a larger report card families can access online or in printed copies that details teacher experience and retention, student discipline rates and other factors.

District officials said the report card offers a clear and accessible way for families to assess a school’s performance. The rating system was developed with input from thousands of parents and other community members.

The report card, Bowser said, provides families with “a set of common, reliable and transparent data . . . that families can use as they make decisions about which school or schools are a best fit for their children.”