THERE WAS a time, not so long ago, when Montgomery County was singled out for its efforts to shrink the achievement gap between black and Latino children and their white and Asian peers.“We are a tall tree in a short forest” was a favorite phrase of Jerry D. Weast, then the schools superintendent, noting progress as well as its relative enhancement by poor results elsewhere. Today, sadly, Montgomery County no longer stands so tall. Instead, like much of the U.S. education system, it struggles to devise solutions for the achievement gap. That should be a matter of urgent concern to school and county officials.

The lack of real progress by the state’s largest school district was spotlighted in a recent report from the county’s Office of Legislative Oversight. The report examined a variety of performance measures, including graduation rates, SAT scores and state exams, and concluded that gaps between black and Latino students and their white and Asian peers had not changed appreciably despite the county’s efforts over the years. “Largely ineffective” was the verdict of the report, which alleged that money earmarked to help students at-risk or from impoverished families was not properly spent...