D.C. Schools Chancellor Antwan Wilson greets students. (Sarah L. Voisin/The Washington Post)

RISING STUDENT test scores. Refurbished schools. That is the backdrop for the start of a new school year for D.C. Public Schools students, and it is a far cry from what existed before school reform. A decade’s investment in public education is paying off, and that is cause for celebration, even given the obvious need to do more to ensure that all children — no matter where they live or what their parents earn — are equipped for college or careers.

Monday’s start of classes was seamless, yet it was not that long ago — before Mayor Adrian M. Fenty (D) got control of schools in 2007 — that the District struggled with even the most rudimentary functions, such as readying classrooms, ordering books and paying teachers. Even worse: Expectations for the majority of students — African American children, many from poor families — were low, and failure was accepted.

The progress the city has made since that sorry time was underscored with last week’s release of scores on the national Partnership for Assessment of Readiness for College and Careers (PARCC). Significant gains across almost all grades and subjects, with all groups of students showing improvements, were a testament to reforms that overhauled a dysfunctional school system and allowed charter schools to flourish. The percentage of traditional- and charter-school students meeting the benchmark for college and career readiness increased in 2017 by four percentage points in English language arts and two percentage points in math.

The performance of the traditional D.C. public school system was particularly impressive, with its students showing gains of 6.4 percentage points in English language arts and 3.5 percentage points in math in 2017. Not only did the public school students show improvement on all grade levels in every ward, but every subgroup — race, economic, special- education status, English-learning status — posted gains. PARCC, administered for just the second time, represents new rigor in measuring student achievement and gives added heft to the results.

Michael Casserly of the Council of the Great City Schools told us he has never seen such gains on PARCC, calling them “quite remarkable.” He credited the system, which has shown steady improvement over the past 10 years, for not resting on its laurels but bearing down on reforms and deepening instruction to overcome barriers of poverty and language.

A significant achievement gap persists, with minority and low-income students lagging behind their white and more prosperous peers. With fewer than a third of public school students considered college- and career-ready, it is apparent, as a spokeswoman for the school system said, that “no one is declaring victory.” What is encouraging is that the District — despite changes in administrations and school leadership — remains committed to reform of a public education system that has failed generations of Washingtonians, realizing there will be no quick, easy fix. The new PARCC scores — and the absence of shocking headlines about the start of school — show a willingness to do the hard work over the long haul, and that holds the best promise for lasting results.