TEST SCORES for D.C. public school students released last week provide unmistakable proof that reforms instituted under mayoral control are working.

Results of the 2012 D.C. Comprehensive Assessment System (DC CAS) announced on Thursday showed steady and solid growth in student achievement over the past five years. In 2007, when then-Mayor Adrian M. Fenty (D) took over the schools and Michelle A. Rhee became chancellor, 27.9 percent of students were proficient in math, and 34 percent were proficient in reading. The results for 2012 — while still woefully unacceptable — are substantially improved, with 46 percent of students proficient in math and 43.5 percent proficient in reading.

Students who were in kindergarten during the first year of mayoral control have posted some of the most dramatic gains. The 2012 class of fourth-grade students, according to figures from the Office of the State Superintendent of Education that also include charter-school students, improved its performance over last year by 5.1 percentage points in math and 4.6 percentage points in reading.

The sustained growth is testament to changes initiated by the Fenty-Rhee team and sustained by Mayor Vincent C. Gray (D) and Chancellor Kaya Henderson. Most significant initially was the determination to evaluate teachers, encouraging ineffective ones to leave and properly compensating the highly qualified.

Some have expressed concern that school reforms are stalling. Ms. Henderson is less of a lightning rod than was Ms. Rhee, and Mr. Gray has not been as single-mindedly focused on education reform — almost to the exclusion of other issues — as was Mr. Fenty.

But there hasn’t been, to Mr. Gray’s credit, a rollback of reform. Changes undertaken by Ms. Henderson, notably implementation of a curriculum and introduction of common core standards, may not grab headlines the way firing low-performing teachers does, but they are no less significant in raising the quality of instruction. It’s worth noting that participation in pre-kindergarten programs, a priority of Mr. Gray, boosted proficiency in later grades.

Obviously there’s no room for complacency. Annual gains in reading were disappointing, particularly since the system invested a lot of energy on literacy. Perhaps there should be more urgency in closing schools and creating chartering options for the public school system. That still fewer than half of D.C. children are reading and doing math on grade level underscores the hard work still to be done.

But no one should lose track of the central fact captured by these latest test scores: The school system is doing a better job than in the past of raising achievement for students. It’s vital to continue in that direction.