D.C. education officials have failed to ensure that the city’s lowest-performing schools are implementing federally mandated changes meant to spur improvement and narrow achievement gaps, according to a new report from the U.S. Education Department .

The report comes two years after the Obama administration granted the District relief from the most onerous provisions of the federal No Child Left Behind law, which required all students to be proficient in math and reading by 2014. Forty-two states have won similar relief.

In exchange for that waiver, states agreed to establish an alternative accountability system for judging schools and forcing changes in those with chronically low performance or persistently wide achievement gaps.

The District has complied with expectations in several key areas, such as establishing teacher and principal evaluations that include student performance as a significant component. And federal officials praised the Office of the State Superintendent of Education (OSSE), the agency responsible for monitoring compliance with federal law, for its efforts to collaborate with the D.C. Public Charter School Board and help schools better reach students with disabilities.

But the agency has faltered in pressing for improvements in the District’s lowest-performing schools, arguably the most important aim of the original No Child Left Behind law. Those schools were supposed to develop plans for improvement in seven key areas, from leadership and staffing to curriculum, family engagement and school culture. The OSSE promised to monitor those efforts and to report annually on the schools’ progress.

The OSSE has not done that, according to the federal report issued last week that outlined several other problems at the agency, including a failure to direct federal Title I funds to the appropriate schools and to include required data on school report cards.

It is the latest in a string of stumbles for the OSSE, which has struggled with high leadership turnover since its inception in 2007.

Last week, the Education Department placed a hold on $6.2 million of the $75 million it had awarded the District under the Race to the Top grant competition. Department officials cited concerns about the city’s management of those funds , which were supposed to be used to improve eight “persistently low achieving schools.”

Education Secretary Arne Duncan told reporters that the need for tighter management stemmed from “concerns with OSSE’s management.”

OSSE spokeswoman Ayan Islam attributed the delayed monitoring of low-performing schools to “internal staffing challenges” and said the agency is putting together a team responsible for the monitoring and “providing the support necessary to help transform teaching and learning.”

She said the agency will outline plans to address that and other problems in its application for an extension of its No Child Left Behind waiver, which expires at the end of the school year. The application is due in May.

The Education Department is in the process of scrutinizing the performance of every state that received a waiver. Federal officials have raised similar concerns in reports on Arizona, Idaho and New Jersey, among other states.

But the District’s neighbors are doing well. The Education Department praised Maryland’s “thorough and comprehensive” approach to reviewing and monitoring improvement plans for the state’s worst-performing schools. The state is meeting all expectations except in teacher and principal evaluations, two areas in which Maryland’s policies are still under review.

Virginia also is meeting expectations in almost all areas, but its school report cards are missing required data that would allow parents and policymakers to compare actual achievement to targets. The commonwealth also must ensure that its lowest-performing schools either hire new principals or demonstrate that current principals can lead a transformation.