How we know

Data and sources

Where does each number come from?

Almost everything here comes from public records: the Town's own budgets, plans and assessment rolls, state data covering every Massachusetts city and town, School Department documents, and federal price indexes.

Each entry says what the source is, where to find it, and what these pages use it for. Sources are grouped by who publishes them.

Town of Brookline

Financial plans and budgets

• What: The Town's annual Financial Plan, FY2006 through FY2027, including the FY2027 budget Town Meeting adopted in May 2026 with the override.
• Where: Budget Central on the Town's website.
• Used for: the forecast's starting point; revenue, spending and staffing by department; debt service schedules; the capital plan; median tax bills.

Long-range financial plan

• What: The Town's FY2027 to FY2031 Long-Range Financial Plan, presented in January 2026.
• Where: Budget Central.
• Used for: the comparison with the Town's own forecast, including the $42.7 million FY2031 gap, and the pension and retiree health schedule.

Audited financial statements

• What: The Town's audited statements for FY2021, FY2022 and FY2024.
• Where: the Town's website.
• Used for: reserves, long-term debt, the enterprise and community preservation funds, and the retiree health (OPEB) liability the forecast rolls forward from FY2024.

Assessment roll and classification hearings

• What: The Board of Assessors' parcel-by-parcel assessment records, FY2009 to FY2026, and its annual tax classification hearing presentations to the Select Board.
• Where: the Assessing Department's pages on the Town's website.
• Used for: the tax bill page (tax rates, the residential exemption, median bills, the average apartment), the land value maps and the split of new growth between new building and renovation.

Building permits and the development pipeline

• What: Building permit records from the Building Department (received September 2026), and the Planning Department's Development Look-Ahead, June 2026.
• Where: provided by the departments; the Look-Ahead was presented to the Select Board.
• Used for: how much renovation adds to assessed value, and the timing of the Chestnut Hill redevelopment.

Town reports

• What: The Expenditures and Revenues Study Committee's Final Report (March 2026), with the consultant RKG's fiscal impact analysis; the Advisory Committee's reports to the May 2026 Annual Town Meeting; the Brookline Fiscal Advisory Committee report (February 2020); and the Select Board's 2030 Roadmap.
• Used for: RKG's cost per home and per student, the open seats in K-8 classes, the fire steps agreed for FY2028 and the police positions to be refilled, the Town's free cash policy, and where the four decisions sit in the Town's own planning.

The May 2026 override

• What: The Town's FY2027 to FY2029 Override Guide.
• Used for: the override's amount and its three-year phase-in.

Pension valuations

• What: The Brookline Retirement System's actuarial valuations, 2014 and 2024.
• Used for: the pension funding schedule to full funding in FY2030, the split of pension costs between benefits being earned now and paying down the old shortfall, and the payroll growth and mortality assumptions the pension cost follows after full funding.

Bonds and credit rating

• What: The official statement for the Town's June 2025 general obligation bonds, from the Municipal Securities Rulemaking Board's EMMA site, and Moody's credit opinion on the Town.
• Used for: when voter-approved school debt is paid off, and the Aaa rating and its reserve threshold.

Community preservation

• What: The Town's Community Preservation Act pages, on the surcharge and on funding.
• Used for: how the 1% surcharge is calculated.

Public Schools of Brookline

Enrollment forecasts

• What: NESDEC's enrollment forecast for the district; the School Department's 2023 demographic study by Cropper-McKibben (revised April 2024); and the 2020 McKibben study.
• Used for: the enrollment path in the base case, and the School Department's own forecast as the alternative.

Budgets, staffing and contracts

• What: School Department budget documents, the Superintendent's September 2026 report, and the teachers' (BEU) salary schedules.
• Used for: school pay, the step and turnover arithmetic behind the 3.7% assumption, and current enrollment.

Commonwealth of Massachusetts

Municipal finance data, all cities and towns

• What: The Division of Local Services' Schedule A general fund revenue and spending for all 351 municipalities, FY2005 to FY2025; new growth for every municipality, FY2003 to FY2026; and Proposition 2½ override and debt exclusion votes.
• Where: DLS Databank reports and Revenue and expenditure data.
• Used for: Brookline's twenty-year revenue and spending history, the comparison of new growth with every other town, and the cross-town estimate of what an added home costs.

School enrollment and staffing

• What: The Department of Elementary and Secondary Education's School and District Profiles: enrollment, staff and spending per pupil, by district and year.
• Where: profiles.doe.mass.edu.
• Used for: Brookline's students per staff member since FY2008, the FY2026 school staff count the forecast starts from, and kindergarten counts for Brookline and peer districts.

Births

• What: The Department of Public Health's annual Massachusetts birth reports, 2005 to 2023, with resident births by town, and for 2024, the Town Clerk's count of births to Brookline residents in the 2024 Annual Town Report.
• Where: Annual Massachusetts birth reports.
• Used for: enrollment per birth in Brookline and peer towns, and why enrollment is falling.

Assessment records, every town

• What: MassGIS Standardized Assessors' Parcels: each town's assessment records, including rooms, value and last sale.
• Where: MassGIS Property Tax Parcels.
• Used for: the share of homes that are family-sized, and their sale prices, in Why families settle elsewhere.

Average single-family value

• What: The Division of Local Services' Average Single Family Tax Bill report, FY2010 to FY2026.
• Where: DLS Databank reports.
• Used for: how single-family values have changed in Brookline and nearby towns.

Federal

Pay and price indexes

• What: The Bureau of Labor Statistics' Employment Cost Index for state and local government workers (total compensation, CIU3010000000000I; wages, CIU3020000000000I; benefits, CIU3030000000000I) and the Consumer Price Index for the Boston-Cambridge-Newton area (CUURA103SA0).
• Used for: the inflation benchmarks in How Brookline got here and the backward test of the forecast.

Census

• What: The Census Bureau's 2010 and 2020 redistricting counts of housing units and population for every Massachusetts city and town.
• Used for: the cross-town estimate of what an added home costs.
• Also: the 2010 Summary File 1 and the 2020 Demographic and Housing Characteristics File for every Brookline block (children by age, homes, owned and rented), with block outlines from TIGERweb, from www2.census.gov, for Students from new homes.
• Also: owners and renters by age of householder, Brookline, from the 2000, 2010 and 2020 Censuses, for Aging homeowners and family-sized homes.

American Community Survey

• What: The Census Bureau's five-year estimates for 2015–19 and 2020–24, every Massachusetts town: ages, households with children, housing type, bedrooms and tenure.
• Where: data.census.gov.
• Used for: Why families settle elsewhere.
• Also: the 2020–24 public-use microdata (individual household records) for the area covering Brookline, Dedham and Milton, and bedrooms by block group (table B25041), for Students from new homes and Aging homeowners and family-sized homes.

This project

The model

• What: The Forecast Explorer and the Excel workbook, both built from the same model as these pages.
• Where: the Explorer and workbook links on the forecast home page.

The code and data

• What: The model's code, the data it reads, the checks that keep the Python model, the Explorer and the workbook in agreement, and the source of every page. The Town's building permit records, which staff supplied for this work, are not included.
• Where: github.com/benjammin-code/brookline-budget-2040.

The whitepaper

• What: "How does construction impact Brookline's town finances?", which this work builds on.

Go deeper

• Assumptions register: What does the forecast assume, and why?
• Glossary: What do the budget terms on these pages mean?
• Forecast Explorer: What happens to the budget under your own assumptions?

Last updated 2026-10-14. What has changed.