The Carlisle Mosquito Online

Friday, October 28, 2005


Crystal ball is cloudy for school enrollment forecasts

A town that is growing older could see 150 to 200 fewer students at the Carlisle School five to ten years from now. But if the town's new affordable housing plan is put into play, and more existing homes turn over to younger buyers, the school could stay within 5% of its present 815 students over the next decade.

These two differing enrollment forecasts were given by the New England School Development Council (NESDC), an organization that provides enrollment projections to school districts across the state, at a public meeting of school and town officials on October 19. The group was commissioned for an enrollment study as part of the latest school Master Plan approved by voters in May at Town Meeting. HMFH Architects of Cambridge was hired with the first step being the enrollment study.

On the surface, the preliminary results show an aging town population and school enrollments declining in the decade ahead due to fewer residents of childbearing age. However, a large housing project such as the proposed town affordable housing plan, or any private 40B developments, could bring more students to the school, the study says.

Both the architects and NESDC met with local realtors, school administrators, and town officials to gather data. Census and real estate data and the school's historical enrollment numbers were used for projections.

Ellen Kelly, demographer for NESDC, used the cohort survival method, a standard used to project school enrollments. It uses historical data on town birth rates over the previous ten years to create a ratio to project how many children will enter the school between birth and kindergarten.

Projecting with current growth and enrollment data

In the first forecast, five-year projections for the school show enrollments could drop by 141 students by the 2010 school year based on expected lower birth rates. The 20-44 age group, the so-called child-bearing cohort, is decreasing. Using U.S. Census data, NESDEC reports this age group declined by 18 percent between 1990 and 2000, while the 45-65 age group grew by 36 percent in Carlisle during the period. According to the census the median age of residents has risen to 42 years-old.

One finding from the study is that many couples choose to remain in their home and neighborhood after their families are grown. Twenty-nine percent of Carlisle residents have lived in their homes for 30 years or more, a fact that may surprise people who live in newer, younger neighborhoods.

The student yield, the average number of students per household, is .49 which is roughly five students for every ten dwellings in town. With new subdivisions the student yield can be as high as double, or about one student per house, the report says.

While from 1995 to 2005 the school population grew by 22% from 664 students in 1995 to 814 this school year, the study says the next ten years could bring a decrease in growth, if there are no large affordable housing developments or other growth.

An average of the last five years was used for the cohort survival ratio for the study. The ratio used for the projections was 1.35 meaning the kindergarten class will be about 135% of Carlisle births five years previous. Historically the kindergarten class grows by another 11% by first grade, and has an average growth of 2-3% per grade, per year, thereafter.

The current growth forecast assumes the following: births will level off at 41-44 per year, housing growth will continue at 22 new building permits per year, the home turnover rate will continue at its current rate of 75-80 units a year, the affordable housing plan is not yet implemented, the cohort survival rate of birth to kindergarten stays constant, and the number of children in private schools stays at present levels.

Projecting with affordable housing, accelerated growth

Since a large housing project would have a big impact on the school, NESDEC used the available data from the new Carlisle Affordable Housing Plan released in June to come up with its second set of projections. The forecast with affordable housing and other growth is for 781 students in five years (-4%) and 860 students in ten years (+5.7%).

With Carlisle at around 1% of affordable housing units, well under the state mandated 10% minimum, the town hopes to take control over the issue and the anticipated growth by building its own housing units for rent or sale. The student yield per unit of affordable housing is calculated by the number of bedrooms. The study assumed that any affordable housing built here would have 2-3 bedrooms and have a student yield of 1.05 per housing unit.

Turnover of existing homes

The study also attempted to account for the impact of an expected increase in turnover of existing homes. When families sell their homes in an existing neighborhood, often families with children move in. Currently 75-80 homes turnover each year according to real estate data.

With a big part of the population moving into the older age groups, there could be an increase in the turnover rate. "The 643 residents, age 60 and above in 2000, can be an important factor in projecting the potential for property turnover. A community can grow in population through the turnover of existing housing stock from families with no young children, 'empty nesters', to families with young children," the report acknowledges.

The age 55-plus townhouse development proposed off of Concord Street would likely spur turnover as some residents downsize by moving within the town after their families are grown.

Financial impact

Former selectman John Ballantine, author of previous school enrollment forecasts, asked how the Carlisle School's needs can be balanced with the high school's needs. Superintendent Marie Doyle emphasized the school will watch carefully to see what happens with the high school, "We need to advocate for the needs of students, while being respectful of what the community will bear."

The regional school committee expects to seek design funds for a new high school in 2007 or 2008. The CCHS feasibility study voted this summer for construction of a new school building rather than make costly major renovations on an aging facility.

Doyle said the school needs a long-term plan to qualify for the maximum reimbursement from the Massachusetts School Building Authority. A moratorium on MSBA reimbursements for new projects went into effect in 2003 when Governor Romney reorganized the office and put a hold on new projects. The school hopes to be ready with a plan when the moratorium lifts and new projects are added starting in 2007.

Aging school buildings

Beyond the enrollment issue, the school is faced with some aging facilities and inadequate space for some departments and teachers. The Spalding building that holds the kindergarten and grade one classes is considered to be in the worst condition. The freestanding circular building near the Castle playground was built in the 1950s.

Steve Friedlaender, HMFH architect, showed a room usage study at the presentation, one measure of school facility use. The middle school classrooms, the gym rooms, and elementary and middle school music and art are in near constant use all day long, except for lunch. "The existing facilities are used extremely efficiently," he said.

HMFH architects will assess the condition of all the school buildings and report to the school on this part of the study in November.

Any building replacement or renovation project at the Carlisle School is likely to take several years from the current analysis study, to seeking approval from voters, to finally beginning construction, a fact not lost on families with older grade school or middle school children. With their children about to go on to high school in a few years, many put their focus on improvements at the high school. John Ballantine pointed out another potential problem for the school as it tries to bolster up its facilities: "If the town population ages, you don't get the support for overrides."

Beyond statistics

While the cohort survival method used by school districts to predict enrollments tends to work in larger school districts, in a small town like Carlisle there are typically variations in the number of annual births and the number of new students who move into town. In a small town these variations can greatly affect the class size from year to year, particularly at kindergarten and the first grade when many families move to town to start school.

NESDEC acknowledges that the cohort method does not always work well in smaller districts. "Small schools/towns are the most difficult to project, as the in/out migration of only a few families makes a great difference."

The study allows that its figures could be off due to key factors. If the birth rate, or housing growth increases, or more properties in town turnover, the numbers of students would rise. Improvements in the school's programs and facilities would also attract more students, the report says. "Ten year enrollment projections are just that — projections; they are not guarantees. Whatever the School Committee chooses to do in making plans, it should take into account the possibility of a 10% swing either way in terms of enrollment at all grade levels."

School Business Manager Steve Moore says the results are preliminary and the school needs to fully evaluate the findings in the enrollment study. "It's a data-driven report," he emphasizes, "We need to further validate the information." The school will continue to seek community input on the building study in the months ahead.

The school plans to both post the NESDEC enrollment study presentation online at:, and to make a copy available at the Gleason Public Library.

How accurate do you think the projections are?

Marie Doyle, Superintendent of Carlisle Public Schools:"While I'm happy to hear that enrollment may level off over the next ten years, the Carlisle Public Schools are already overcrowded. Due to educational changes such as requirements for additional smaller learning spaces for literacy, math, special education and an increased population over the last decade, we utilize every available space on this campus. It would benefit the community to have adequate space to respond should there be a surge in school population from 40B developments or other unplanned growth.

Enrollment is only one piece of the puzzle. We are faced with an aging infrastructure as well. Three buildings have roofs that have leaked this fall. It is imperative that we complete our Master Plan and appropriate funds to address the school's needs before we are faced with significant costs to repair buildings whose life span has expired, or to provide temporary space for classrooms. The enrollment report does not eradicate the pressing building needs of the school."

Christy Barbee, School Building Committee Chair: "I don't buy it that we'd lose that many students. The school numbers have been at least a little ahead of past projections. The study did not take into account if the town's affordable housing project targets are not met, and uncontrolled growth occurs with private affordable housing projects."

Barbee says there are ways to design flexible school space that the committee will discuss with the architects.

Steve Moore, School Business Manager: "The first set of projections is in decline because growth is not happening. The question is when will growth happen, and how much?"

Moore said the school knew that enrollment projections would go down based strictly on historical data on recent birth rates. Five-year projections tend to be the most accurate based on historical data. But, he emphasizes the cohort survival method of enrollment projections doesn't always work well in small towns. The key assumption in the lower projections is that nothing changes, he said, and everything stays the same. The school hoped the second set of projections would answer what realistic growth looks like for the school.

John Ballantine, former Selectman, author of previous enrollment studies: "The school population will remain stable or decline for a period of time as baby boomers age and until the baby boomers' children move in with families, maybe in 10 to 15 years."

He said actual enrollments will likely turn out to be somewhere within the wide band of ten year projections that range from a low of 600 to 860 in the high projection. Ballantine estimates that the mid-700s is the most likely school population over the decade.

The large classes of middle school children will move up and out of the school system and be replaced by smaller classes, he said, and the birth rate will not increase based on the age of the population. Regardless of population growth, he agrees that many of the school's facilities are older and in need of refurbishment.

2005 The Carlisle Mosquito