Montgomery County students’ gains in math and reading are slowing, leaving some schools officials to question if the modest improvements are enough to reach the system’s long-term goals. Just 11 percent of middle school students scored below proficiency on the Maryland School Assessment reading exam, down from 11.8 percent in 2009.

But the rate of improvement is slowing from past years: From 2004 to 2008, these students’ ratings climbed an average of 2.75 percentage points each year, but this year, the pace slowed to 0.8 points.