Wilton public school enrollment is expected to taper off mildly over the next few years, according to a recent forecast released by the Board of Education, which draws on a variety of analytical tools.

"The objective of my work is to provide a basis for next year's school budget," said Ellen Essman, who provided the report to Schools Superintendent Gary Richards. The report was discussed at the Board of Education meeting on Thursday, Oct. 25.

Taking into account a student body of 4,239, predictions were released as follows: 4,179 in 2013, 4,130 in 2014, 4,042 for 2015, through 2020, which yielded an estimated enrollment of 3,693.

Other than birth rate data, the decreasing enrollment forecasts were based on housing starts, private school preference rates, parochial school capacity, "perceived quality of schools," trends in school start age, among other factors.

Ms. Essman included the methodology for gathering facts and the analytical tools used for the prediction in her report. Her first step was obtaining last year's enrollment figures, which were used comparatively with this year's student body tally, which was completed on Oct. 1.

Because Connecticut no longer prepares enrollment projections for Wilton, the district has taken it upon itself to do so. Its best model has been using "migration numbers," which take into account the trend of the last five years.

For example, the school board was able to calculate a migration from 2011 to 2012, which compared last year's kindergarten class of 274 students with this year's 289. This gives a kindergarten class migration number of positive 15.

In order to "smooth any anomalous data," Ms. Essman went back four years prior to establish a reliable pattern.

The method allowed for a 2013-2014 enrollment forecast by extending the migration pattern to this year's class size.

"Migration numbers help in that they catch a picture of your specific town," she said. "If your town has a school system that attracts parents with young children, such as Wilton, this will show up in high migration numbers near the beginning of school."

Birth rates played a major role in explaining a forecasted downward trend in class sizes.

"The Wilton birth rates for 2008-2011 are lower than the period 2003-2006," Ms. Essman said, with "2006 at an all-time low of 63. As a result, the entering kindergarten is projected to be lower than previous years."

Reviewing Wilton statistics, she said it is the K-5 numbers that are most susceptible to change. The higher grades appear relatively stable.

The report of class size predictions recommended the Board of Education monitor the steady decline closely, especially if the housing market rebounds more quickly than expected.

"New housing starts or significant increase in real estate transactions could impact this projection, although currently the (real estate) market is slow," she said in a report addendum.

The total net migration for all grades this year was negative 23, which deviates from last year's prediction of minus 37 by 37%, which underscores that predictions are subject to change.

Information: wilton.k12.ct.us.