Guest Contribution by Arthur Green
We have criticized the TRSD administration, school board and budget committee in the past for refusing to acknowledge the persistent long-term decline in Timberlane enrollment. The lastest episode in this determination to avoid facing facts was the decision of the School Board on Nov. 3 to forego the annual enrollment forecast which is provided by NESDEC as a no-charge benefit of our district membership in that organization.
It is nearly incomprehensible that an organization responsible for a $70 million dollar budget would not want to have all available information about the forecast outlook for its served population. True, forecasts are only forecasts, and need to be leavened with experience and local knowledge. But the refusal to accept this freely available professional forecast is due entirely to the politics of declining enrollment.
Fact: Overall school district enrollment has declined each year since 2007/08.
Fact: Since that year, enrollment is down from 4,625 to 3,566 (tuitioned students not included), a decline of 1,059 or 23%
Fact: The enrollment decline was forecast by NESDEC with great accuracy. For example, in November 2011, their forecast for 2016/17 was 3,518, off by just 1.35% from the actual enrollment this year. This is remarkable because at the time of this forecast, enrollment was 4,147.
Fact: TRSD does forecast enrollment, although only for one year out, and only by building, not by grade. The TRSD forecasts for the last three years have been consistently much higher than the actual enrollment each year. We do not have a the history of prior year forecasts by the district, if any.
Since we will not receive a NESDEC forecast this year, we have done a “reality check”evaluation (details below) and find that we can reasonably expect further enrollment decline next year of 47 students (and possibly more). The district is forecasting an enrollment increase of 11 students.
This does not mean that we are in the business of enrollment forecasting. It does mean that the district ought to be taking advantage of the best possible professional advice about the enrollment outlook, especially for the years beyond the 2017/18 year currently being budgeted.
The NESDEC forecast last year was that enrollment would decrease by 83 from 2016/17 to 2017/18. The informal analysis here arrives at a decrease of 47. What seems more likely – an enrollment decrease in the range of 47-83, or an enrollment increase?
The modus operandi of the administration and its supporters:
- Each year, downplay the enrollment decline for the coming year by issuing unsubstantiated forecasts which exaggerate expected enrollment
- Proclaim eagerly that, just because we will have 20 fewer students, we can’t reduce teaching staff, because that decline is spread across classrooms all over the district
- Complain that for a particular grade level in a particular building in a particular year, the NESDEC forecast was over or under. (Don’t provide enough detials to check this claim. And certainly don’t provide NESDEC with corrected information to improve the forecast quality.)
- When the actual enrollment for the following year turns out to be much less than the district forecast, change the subject to the future year being budgeted.
- Rinse and repeat.
- Result: Discussion of the need for staffing reduction is postponed by another year.
Technical Note: Detailed Calculations based on the current enrollment

The first column is the current 2016/17 enrollment (including tuitioned students).
The second column begins to look at 2017/18 by taking the students we have this year, and advancing them by one grade (“advance cohort”) for each group starting from the Kindergarten cohort advancing to Grade 1 next year. This needs to be adjusted for Pre-K and Kindergarten, because Pre-K has a range of ages and does not advance to Kindergaten as a single group. For simplicity, let’s start by assuming that Pre-K and K are the same as 2016/17 (don’t worry, we are not done). With these assumptions, the students we already know about give us an enrollment forecast of 3,473.
The third column, “Cohort Adjustment”, uses the NESDEC analysis from last year to recognize that each cohort may have more or fewer students when it advances to the next grade. For example, NESDEC forecast the the Grade 1 cohort advancing to Grade 2 would gain 5 students. These gains and losses come from multiple factors. It could reflect families moving into new houses. In the Grade 11 to 12 cohort, it recognizes that some of the Grade 12 students will be held over from Grade 12 in the prior year. In the Grade 8 to Grade 9 cohort, there is a pattern of students electing to go elsewhere for high school. Pre-K and K are again the exception, because those groups are not filled by an advancing cohort. In those cases, I have used NESDEC’s forecast enrollment change. Overall, the cohort adjustment adds 61 students to the base forecast.
The next column, Forecast 2017/18, adds the Cohort Adjustment column the Advance Cohort column. The net result is a 47-student decrease in the district enrollment, although elementary enrollment increases by 32.
The final column is the TRSD forecast assembled from the budget documents. The district is forecasting an increase of 11 from the current year.
What can we reasonably conclude from this analysis, since any forecast is subject to error, and we will not know the true enrollment until next fall? Still, there are some observations we can make:
- We know this year’s enrolled student body, and based on that alone, we know that enrollment next year will be lower by over 100 unless external factors change.
- We have a professional forecast created last year which is based on demographic factors such as births, home sales and building permits, and which has documented the net impact of those external factors (the “Cohort Adjustment” column). A reasonable expectation from that analysis is that those factors could add about 60 students.
- We have a forecast from TRSD, which employs no stated methodology, and which, if correct, implies “cohort adjustment” factors double those estimated by NESDEC. For example, elementary enrollment is forecast by the district to increase by 75 from this year, but that is actually an increase of 108 from the known current cohort as they advance by one grade next year. Let me walk through that statement. This year, elementary enrollment is 1,553. As those students advance by one grade, the enrollment next year would be 1,520, or 33 fewer students. NESDEC has assessed cohort adjustments adding 65 students, which would bring elementary enrollment to 1,585, or 32 students more than this year. But TRSD is forecasting 1,628 elementary students, so the implied cohort adjustment would need to be 108 instead of the 65 forecast by NESDEC. The adminstration could be correct, but what is the method, and where is the evidence to substantiate their number?
Like this:
Like Loading...