THE CONCLUSION by the D.C. inspector general that there was no widespread or systematic cheating in the public schools during the early years of school reform comes as no surprise. The findings mirror those of other investigations into the issue and of subsequent tests — including those administered under unassailable security procedures — that affirmed the gains by D.C. students in reading and math. It is time to put to rest unfounded suspicions about supposed wrongdoing and acknowledge the progress of the city’s public school students.

D.C. Inspector General Charles J. Willoughby, with an assist from the U.S. Education Department’s Office of Inspector General, released a report this month that examined allegations of possible improprieties in standardized reading and math exams administered from 2008 to 2010. Chancellor Kaya Henderson requested the review last year after questions were raised in a USA Today report about unusually high numbers of erasures from wrong to right answers. A private firm hired by the school system to investigate the matter found no widespread problems, but Ms. Henderson asked for another look out of an abundance of caution.

Mr. Willoughby’s investigators focused their efforts on Noyes Education Campus, which had been highlighted in press reports. The investigation — which included interviews with current and former staff at Noyes, test monitors and parents — found one instance of one teacher who admitted to coaching students. Although the teacher, who was terminated in May 2011, said it “seemed” it was “understood” that this was how testing was done at the school, investigators found no corroboration. All the parents interviewed said that they believed that the scores their children achieved on the exams were indicative of their overall school performance and consistent with other test scores. Investigators catalogued a number of plausible reasons for the erasure marks. Finding so little at Noyes and lacking any credible evidence of systematic wrongdoing, the inspector general — much like two private firms separately hired to investigate cheating concerns — concluded there was “insufficient evidence” to warrant a wider probe.

The report received a mystifying reception from officials representing those on the front lines of learning. Instead of cheering news of confirmed achievement by D.C. students, Randi Weingarten, president of the American Federation of Teachers, and Nathan Saunders, head of the Washington Teachers’ Union, seemed disappointed that no widespread cheating was found. Both faulted the inspector general’s methodology and urged even more investigation.

The test scores Mr. Willoughby examined don’t exist in a vacuum. Other tests — including the non-cheatable National Assessment of Educational Progress and D.C. Comprehensive Assessment System tests administered under tightened security protocols — also have shown improvement.

Why is it so hard to accept that children in the District of Columbia are making progress? Or that their teachers can produce results without having to cook the books? Some union officials don’t like using test scores to hold schools and teachers accountable, and they’d like to discredit former chancellor Michelle A. Rhee and the reforms she ushered in. But can’t they give their own members a little credit for what they’ve accomplished in the past few years?