NEW MILFORD — School officials have found the cause for the nine-point drop in graduation rates, saying the bulk of those students actually graduated, but weren’t counted in the stats because the reporting window closed earlier.

New Milford’s four-year graduation rate for 2017 was 82.2 percent, down from 91.5 percent reported in 2016. After the state published the figures this month, school officials began looking at their internal reporting practices to see what happened with those students — 36 of them.

Last week, Superintendent of Schools Joshua Smith announced that 25 of those students did graduate in four years and should have been factored into the four-year graduation cohort. These students are in the special education program; they are allowed to complete their high school education in the summer and still be counted as earning their diplomas in four years.

Historically, districts are able to adjust their numbers to include these students, but this year the federal reporting window closed earlier and they could not be added, Smith said. He said several other districts encountered this problem.

He said the reported graduation rate also incorrectly included six students in the special education program for 18- to 21-year-olds at Litchfield Hills.

“Nowhere in the state do these students count in the four-year cohort,” Smith said.

Once these 31 students are factored out, Smith said the district’s graduation rate is actually 89.5 percent, which is just 2 points less than 2016, and higher than the state average of 87.9 percent.

“Our numbers are going to fluctuate a point or two year to year,” Smith said.

He said the district has changed its internal reporting process to ensure this doesn’t happen again, but said the 2017 figures cannot be corrected.

“I’m going to go on record that New Milford will see a huge spurt next year,” he said, adding that any recognition from the federal government for this growth shouldn’t be taken too seriously.