WILTON — The methodology used to predict the ongoing decline in school enrollment numbers was explained to the Board of Education Thursday night by its longtime consultant.

“This is just … a sense, if you will, of what the future enrollment will be looking like in Wilton, Connecticut,” explained Ellen Essman, who predicted that total K-12 enrollment will decline by 54 students next year, from its current 3,814, to 3,760.

Though she is predicting more kindergarten students will enroll in the 2020-21 school year—717, or 19 more, than the 698 that entered in 2019-20—she also believes enrollment will drop in grades 3-8 by a combined 75 students.

“This is crucial to the budget,” said Debbie Low, who is the new chair.

A larger dip is predicted the following year, with a decrease of 83 students in 2021-22, to 3,677.

According to Essman’s long-term projections, numbers continue to decrease through to the 2027-28 school year. At that time, she estimates, total K-12 enrollment could dip to 3,476 that year—a total reduction of 338 students from this current year’s enrollment.

Asked why the numbers were decreasing, Essman said, “There’s a host of reasons.”

“Some people put their kids in private school … There are people moving in and out of the community,” she said.

Essman said that she uses what is known as the “cohort retention method” to determine her numbers, which focuses on averaging student migration over a five-year period.

“The cohort retention method (is) a history of the enrollment in order to come up with averages of migration class to class,” she said.

More difficult to determine are the numbers for incoming kindergartners, she said, given that not all future Wilton Public Schools’ students are attending preschool in this town. Toward that end, Essman and her team reached out to surrounding preschools, as well as local ones, for data.

“I was trying to get a handle on how many preschoolers there are out there,” she said, noting that there are also some children that don’t even attend them.

“Trying to pin that number down is a little more challenging,” she said, affirming she believes her numbers are still likely very accurate.

Meanwhile, Superintendent of Schools Kevin Smith presented his annual Class Size Report to the board, noting its importance as it relates to the budget planning in particular.

“It gives us a 10,000-foot view of all of our staff and where they are, as well as all of our classroom teachers and how many students are in those classes,” he said.

“I would say that on the whole we are operating inside our class guidelines, and in a couple of cases under our class guidelines,” Smith said.

Currently, the kindergarten average class size is 18 students, he said, with grades 1-4 averaging at 20, and grade 5 at an average of 22.

Grade 6, he said, being a smaller cohort, averages 18 to 22 in size, and grades 7 and 8 average around 22.5.

“Once you get into the high school you see quite a bit of variance,” he said, “and that is really a function of scheduling and the courses that are available.”

“The variances in the class sizes in the high school are very drastic,” Vice Chair Glenn Hemmerle noted.

“The numbers on paper can be deceiving,” Smith explained, with the document also listing independent studies that may involve just one student, as well as Individualized Education Plans (IEPs) that may require special education accommodations.

“There are so many variables involved in some of the numbers,” said Robert O’Donnell, Wilton High School principal, with fluctuations resulting from course selections and, in some cases, opportunities to combine smaller groups.

“The high school works really hard to accommodate student selection,” Smith said.

The report notes a total 588.6 full-time employee (FTE) equivalent for the entire district, with 578 FTE last year and 591 FTE the year before.

“I appreciate that there’s some history here too,” Low said, “so you can see trends and changes.”