Children line up before a graduation ceremony at the Carlos Rosario Public Charter School. A rating system will rank D.C.’s public charter schools. (Lucian Perkins/The Washington Post)

Mayor Vincent C. Gray and members of the D.C. Public Charter School Board, which devised the new framework, are scheduled to roll out this year’s rankings at an early afternoon press conference.

The new framework contains some information already available in annual performance reports issued by the board, which is empowered to open schools and close them for poor performance. But it also features rates of test score growth showing how students at a school have advanced in a year’s time relative to their academic peers across the city. Schools will also be assessed against a series of leading indicators and “gateway” measurements that researchers regard as predictors of future educational success, such as third-grade DC CAS reading scores, 8th grade math scores and 11th grade PSAT results.

Early childhood and adult education programs will be largely exempt from the new ratings, officials said, because the differences in their approach make them difficult to compare. Governance and financial management, two major problem areas for charter schools, are also not addressed in the ratings.

The assessments are likely to draw the greatest attention for dividing most of the city’s 53 charter schools (located on 98 campuses) into three tiers of overall quality, based on student achievement, annual growth, gateway measurements and leading indicators such as attendance, re-enrollment and numbers of ninth graders on track to graduate.

The measurements are converted to a 100-point scale. Schools with at least 65 points will land in Tier I, or the “high-performing” category, followed by “mid-performing” schools in Tier II (35 to 64 points) and “low performing” schools in Tier III (0 to 34 points). Schools scores below 20 points may be subject to closure.