How we know

What has changed

What has changed in the forecast, and when?

The forecast is updated as new data arrives and as its methods are checked. Each change that moves a published figure will be listed here, newest first, with what moved and why.

The first version was published in October 2026. Changes are listed from 27 October 2026 on.

31 October 2026: Chestnut Hill, from the approved plan to the special permit filing

What changed. The forecast now counts the Chestnut Hill Office Park project as filed for its special permit: 384 homes, a 187-room hotel, 41,284 square feet of retail and 93,741 of medical office, per the Town's October 2026 project page. Before, it counted the plan Town Meeting approved in May 2026: 266 homes and a 200-room hotel. The timing is unchanged, with revenue and costs ramping in over FY2032 to FY2034. Its property tax is priced from the published scenarios' own rates, about $5.0 million a year (FY2025 dollars) instead of $4.5 million, and the added homes bring more students and service costs. Chestnut Hill: how it's counted sets out the calculation.

What moved. The base case's room in FY2040 is $12.4 million, up from $12.0 million. One point a year of extra pay growth for all staff costs $42.4 million a year by FY2040, up from $42.3 million. The override that would close that gap is about $22.2 million, down from $22.6 million, adding $1,885 to the median single-family bill by FY2040 instead of $1,912. Enrollment runs about 15 students higher from FY2032 on (5,941 in FY2034, up from 5,926).

31 October 2026: the assessors' count of homes, one more year

What changed. The count of homes on the Town's assessment rolls now runs through the January 1, 2025 roll, one year further, and its cleaning is stricter. It no longer counts one year's recount of lots with more than one house (each such lot went from one home to two with nothing built), or units at tax-exempt residences and a hospital. The January 2025 roll adds 273 homes, most of them in six buildings the assessors first recorded that year, several of them still under construction at the time.

What moved. The rolls now show 1,082 more homes from January 2016 to January 2025, about 120 a year; before, they showed about 110 a year to January 2024. The forecast did not change: it counts new homes from building permits (about 105 a year since 2016), and the rolls are a check on those permits. They still agree: permits issued from 2015 to 2023 net 1,214 homes, and the rolls gained 1,194, counting assisted living in both.

27 October 2026: the cost of a student filling an open seat

What changed. When students from added homes fill seats in classes that are already running, the forecast now charges about $7,760 a student a year (FY2027 dollars) instead of $2,497. The new figure adds special education at the district's average rate and cost to the supplies and other costs that grow with each seat, because special education staff and services grow with enrollment even when classrooms don't. Schools: three tiers for the cost of an added student sets out the calculation.

What moved. The base case did not change: it already charges $16,975 for every added student. Only the cases where added students fill open seats moved:

A $434,000 rental apartment whose children fill open seats now brings the Town about $1,700 a year more than it costs, down from about $3,000.

Also updated. Open seats now use the School Department's October 1, 2026 counts: 4,436 students in kindergarten through grade 8, about 1,100 open seats under the class-size guidelines and about 440 with every class kept three students below them. These are text updates; the forecast's figures did not change.

Last updated 2026-10-31. What has changed.