Sixth grader from Deal Middle School, Marina Pariser, 12, takes notes in class. (Sarah L. Voisin/The Washington Post)

AFTER THE historic improvement in D.C. student test scores last year, the modest gains from this year’s testing seemed anticlimactic. Indeed, even D.C. Schools Chancellor Kaya Henderson said she was “disappointed” that the system didn’t demonstrate greater growth. But no matter how small the gains, it’s important not to lose sight of the fact that public education in the District is moving in the right direction and should not be derailed.

Results from the standardized D.C. CAS tests administered in March and April showed proficiency in reading and math inching up for both traditional- and charter-school students. In the traditional school system, 51 percent of students are proficient in math, up 1.6 percentage points, and nearly 48 percent are proficient in reading, up 0.3 percentage point. Nearly 60 percent of charter-school students are proficient in math, up one point since last year, and 53.4 percent of charter students are proficient in reading, up 0.4 percentage point.

The gains, announced Thursday, become more meaningful when viewed as a measure of how far public education has come in the District. Consider that in 2007, when mayoral control of the public schools was implemented, just 27.9 percent of students in the traditional-school system were proficient in math. So it’s something of a milestone that more than half of the system’s students are now proficient in the subject. Charter school students performed above the District average in math and reading for the ninth straight year.

Of course, the results also underscore just how much work is still to be done. No doubt 51.1 percent of students able to do math is better than 27.9 percent, but it is nonetheless completely unacceptable. Results showing English-language learners and Hispanic students struggling in both sectors, with declining proficiency rates, are cause for concern, as is the continuing gap in achievement between African American and white students.

New funding formulas are being implemented to target students most at risk, and Mayor Vincent C. Gray (D) and the D.C. Council have invested new dollars to help ratchet up the work. Other things that need to be done — such as providing more instruction time through an extended day — have encountered obstacles that need to be overcome. The next mayor will have his or her work cut out, but it’s encouraging that the pieces are in place to continue the positive momentum of school improvement.