As a federal deadline approaches for making all students proficient in English and math, officials in some top area school districts find themselves in an unfamiliar position — explaining why their schools aren’t making enough progress.

A Globe review of this year’s MCAS results, released this month, shows that just under half of area schools — approximately 133 out of 269 — met the “adequate yearly progress’’ standard set under the federal No Child Left Behind law.

Nearly every school district in the area had at least one school that did not meet the standard — including such high-performing districts as Arlington, Belmont, Brookline, Newton, Wayland, and Wellesley — and some school officials said the numbers paint an unfair portrait.

“You’re left with the impression that you’ve got a failing school,’’ said Lexington Superintendent Paul Ash. “When you’re already at the ninety-eighth, ninety-ninth percentile, you have to make a certain amount of growth above that level, and it’s just not possible.’’

Under federal law, all children are supposed to be proficient in English and math by 2014, and schools are measured against benchmarks each year to determine the progress of all students, as well as subsets such as special education or low-income students. But as time goes by, those benchmarks creep closer to 100 percent, making it harder for schools to come in over the bar.

“There’s more difficulty reaching that target, even though we’re seeing progress and students improving performance over the years,’’ said Christine Brumbach, director of student development in Needham. Four of Needham’s eight schools met the target this year.

Statewide, 57 percent of public schools fell short of the yearly progress standard.

Four of nine schools in Lexington — a district in which more than 98 percent of tenth-graders scored advanced or proficient on their math and English MCAS exams — did not meet the standard.

Ash said that, while Lexington schools aren’t perfect, the real problem lies in the benchmark that penalizes anything short of steady progress toward perfection.

“The formula is insane,’’ Ash said. “I just shake my head. When we get to 2014, we’re going to have nearly 100 percent of the schools in Massachusetts not making adequate yearly progress. How can that make sense?’’

Consequences for failing to meet the benchmarks range from schools having to notify parents of the school’s status, to allowing families to choose other schools, to, in extreme cases, abolishing or restructuring a school district.

Ash said Lexington will have to send letters home this year notifying some parents of the schools’ status, although he doesn’t foresee more serious consequences later on.