Kindergarten students at Democracy Prep Congress Heights in southeast of Washington, D.C. (Astrid Riecken/For The Washington Post)

More of the District’s students are enrolled in high-performing public charter schools this year, according to ratings that the D.C. Public Charter School Board plans to release Friday.

More than 12,000 students — nearly one-third of the city’s charter school students — are enrolled in charters ranked in the highest of three performance tiers, an increase of 9 percent from last year.

In all, 22 charters were rated in the top tier, including seven that received that designation for the first time. The top category includes schools from nearly every ward in the District and represents a wide range of instructional approaches, including Chinese immersion, Montessori, project-based learning and a boarding program.

“As the city’s sole authorizer, we aim to open charter schools that add to the quality and diversity of the D.C. education landscape,” John H. “Skip” McCoy, chairman of the D.C. Public Charter School Board, said in a news release. “Today’s results show that this is happening.”

The rating system — known as the Performance Management Framework — has been in place since 2011 and aims to evaluate performance and compare the quality of the city’s 112 charter school campuses.

The results can carry ramifications for charter schools, which serve 44 percent of the city’s public school students. Schools rated highly tend to attract more applicants and fundraising dollars, and the classifications inform decisions that the board makes about whether charter schools should be expanded or closed.

Charter officials plan to release the results at Friendship Public Charter School at Chamberlain in Southeast on Friday morning with Mayor Vincent C. Gray. In a statement, Gray (D) called the latest results “evidence that charter school quality is continuing to grow.”

Although enrollment in high-performing schools rose, the actual number of Tier 1 schools dipped this year from 23 to 22. The number of Tier 2 schools remained the same, 37. There are five Tier 3 schools, down from eight last year.

Many low-performing schools have closed in recent years. This fall, two struggling charter schools — Imagine Southeast and Arts and Technology Academy — were taken over by new operators with stronger academic records.

The rating framework’s formula is built on a 100-point scale that weighs academic progress, proficiency on standardized tests, graduation rates and attendance, among other measures. The most weight is given to academic progress, which measures how students in the school perform over time compared with similar students in other schools.

For the first time, the charter board released performance reports for adult education and early childhood campuses, although it did not place those schools in tiers this year.

Next year, the rating system will change as schools transition to standardized tests aligned to more rigorous academic standards.

The charter board has devised a way to continue measuring academic progress even as the tests change. At the same time, it will not hold schools responsible in the first year, so no schools will be labeled as Tier 3 or be subject to any ramifications that go with that designation.

This year, Center City Public Charter School in Congress Heights became the first in the city to move from the lowest tier to the top tier.

Russ Williams, the president and chief executive of Center City Public Charter Schools, attributed the success to strong leadership, curriculum improvements and a renewed focus on instructional development.

Niya White became principal at the school in 2011, when it was rated Tier 3. She worked to make the climate more positive and the instruction more effective and challenging. She rewards students each day for good behavior and academic progress. She also reduced the number of teacher evaluations so she could spend less time scrutinizing teachers and more time co-teaching and helping them improve.

Her charter school had some of the highest measures for academic growth in reading this year.

White said earning a Tier 1 designation would not change much at her school day to day. “We’ll continue to work hard,” she said. “But this is definitely something that everybody will be proud to hear.”

Center City, which operates six charter schools — all converted from Catholic schools — shows how charters can rise and fall on the board’s framework.

Its school in Brightwood has been a top-tier school for three years; a school in Petworth dropped this year from the top tier to the middle; and a school in Trinidad dropped from the top tier in 2011 to the bottom this year.

Williams said variability year to year can often be attributed to changes in leadership and staff as well as the increasing performance expectations that the charter board sets. He said he is working to improve the curriculum and instructional quality across all the charter’s schools.