Projecting Student Enrollment

The county, who released its revised projections in February 2005, predicted WCPSS will reach 118,041 students - an increase of more than 3,900 over last year's official 20th day number. If first day figures are any indication, however, the increase could be closer to 6,000. Last year, WCPSS had 108,353 students on the first day of school; this year, we already had 114,375 - a gain of 6,022. Yes, 6,022!

Each school reports its enrollment on days 1, 5, 7, 10 and 20. WCPSS uses the 20th day numbers as the official enrollment because historically, a substantial number of students don't show up or register until after Labor Day. For example, last year's official 20th day enrollment was 114,068, meaning an additional 5,715 students enrolled after the start of school.

So, where do enrollment projections come from? How are the numbers derived? How accurate have they been in the past?

The county and the school system agreed to use the county's projections for long-term planning purposes, and together, have worked with consultants to help project student enrollment for the next school year, for the six planning areas and for 20 years out. These computer models are run at four different times per year. Some of the data is built into the models, while other information is entered on a yearly basis.

The models rely on such data as that from census counts, Wake County resident population projections, yearly births, student enrollment numbers, figures derived from aging students forward, new registrations and current and historic student distribution by residence. Other factors such as the migration of residents into and out of the county, the influx of undocumented immigrants and enrollment levels in private, charter and home schools also play a role in the projection models.

Each year, Dr. Ramey Beavers, senior director for the Office of Growth Management, computes projections on enrollment for each individual school for the upcoming school year to aid with staff allocations. His figures are developed by using a number of factors such as aging students forward, looking at the past history for each grade level and planning area, and analyzing the growth taking place in individual nodes. Once the figures are computed, he shares them with principals who let him know if the figures appear high or low based on their knowledge of enrollment and new subdivisions being built. Once adjustments are made, these are the numbers that the system uses to begin the planning process. Each year, the computer models are updated after the official 20th day numbers are verified.

In the past, enrollment projections have been extremely close to the actual enrollment numbers. For example, the Jan. 2001 projections for 2001-02 school year differ from the actual 20th day enrollment numbers by only 0.08 percent. This is exceptional considering that the industry standards are a 5 percent to 10 percent deviation.

However, when you are dealing with a school system with more than 114,000 students, having an enrollment projection that is off by as little as 1 percent is equivalent to more than 1,000 students.

"A projection is a projection - it's a sophisticated guess, but it's still a guess," said Beavers. "We work hard to get it close, and it usually comes in close. But if we're off by just 1 percent - that's 1,000 students. One percent is good, but not when it equates to a thousand students. That's an elementary school and a half of students. The bottom line is that the budget is built on the belief that we are going to have a certain number of students."

Unexpected fluctuations in the population are tied to socio-economic changes and expectations and are harder to predict. Unexpected factors such as being named "best place to live" can have an impact on the long-term projections in a significant way. As a result, while short-term predictions (about one year ahead) are usually within .5 to 1 percent of the actual values, longer-term predictions may accrue larger margins of error.

Based on the county's best projections, a student enrollment of 187,363 students is now expected for the year 2020 - approximately 27,000 students more than earlier estimates. The new figures reflect faster migration into Wake than previously projected, as well as the number of students who enrolled over the past two years after leaving private, charter and home schools where growth trends are down.

There's a lot riding on student enrollment figures. They affect many different areas including the size of the budget, the need for additional classroom space, the location and construction of new schools, staffing levels, supplies, placement of mobile units and the assignment of students to schools.

Wake County Planning reports the projections as a low to medium to high range. The school system agreed to use the county's upper projection for capital planning (facilities) and the mid-point - what's reflected in this blog - for operations (budget).

Click here for a graph comparing actual enrollment and annual projections:http://www.wcpss.net/demographics/projections/images/comparison-proj-actual.pdf