Topic

New homes and the budget: is there room?

When Brookline adds homes, does the budget follow, does the Town have room for them, and what would show that it needs more?

Revenue follows construction closely, about two years later. Costs have not followed individual homes. By some measures, the services new homes use most seem to have room. The schools have about 1,100 open seats in kindergarten to grade 8 and enrollment is falling, and fire and police workload is below common marks of a busy department. If that holds, a single project's estimate overstates what its homes cost the Town. But these are measures taken from budgets and reports, not the judgment of the people who run those services, and services often strain in other ways before any measure says they are full. Where each one's limit lies is not known. A few readings, most of them published each year, would show which way things are moving.

Most of what a new home costs the Town is a share of services that are already running: a seat in a classroom, a place on a fire engine's route, a patrol car's time. Whether that share is a real new cost depends on whether the service has room. This page compares the two ways of estimating what new homes cost, checks each against what has actually happened in Brookline, sets out where Brookline stands service by service, and lists the readings that would show the room running out.

Two ways to estimate what new homes cost

The project estimate. A fiscal impact study for a single building adds up the tax its homes will pay and subtracts a share of what the Town spends: an average home's share of police, fire and other departments, and the cost of the students an average home of its kind sends to school. That is the method the Town's consultants use, and it is the one on Growth: when a new home pays for itself. It assumes the budget moves home by home, with each project's costs arriving alongside its revenue.

The town-wide view. The other way starts from the services. It asks whether the schools, fire companies and patrols the Town already pays for can take more residents, and at what point one of them would need another teacher, company or building. Below that point an added home costs little beyond supplies and the like. At that point, one project can tip a whole new cost.

The two can give very different answers for the same building. Take 100 rental apartments at about $521,000 of assessed value each, the recent Brookline average. They would pay about $530,000 a year in property tax. Rounded, in today's dollars:

When each is right. The standard handbook on the method, Burchell and Listokin's Fiscal Impact Guidebook (1978), says the average-cost approach works when a town's services closely match current demand. Where there is spare capacity, half-empty classrooms or a fire company that can take more calls, it overstates what growth costs. Where a service is full, it understates it, and the project that tips the service over gets charged for the whole new facility. The handbook and later practitioners agree the two approaches meet over the long run and across all of a town's growth together, but not for one project in one year.

Three further findings from the research shape how this page reads Brookline's record:

• Projects do not add up one at a time. Each project is estimated against today's capacity, so the cost that the fifth project triggers was caused by all five (Kotval and Mullin, Lincoln Institute).
• The estimates have hardly ever been checked. No published study was found comparing a project's fiscal estimate with what later happened. One review of the field (Edwards and Huddleston, 2010) found that ready-made models can be wrong by a wide margin, sometimes about whether a project comes out ahead or behind.
• Room is not the same as no cost. When spending stays flat while a town grows, the cost can show up as thinner service for everyone, fewer officers per call or fuller classrooms, rather than in the budget (Paulsen, 2014; Ladd's studies of U.S. counties, 1992 and 1994). That is why this page pairs each sign of room with a reading that would show it being used up.

The rest of the page tests the town-wide view against Brookline's own record: whether revenue and costs have actually followed homes, and what the published measures suggest about room in each service.

Revenue follows construction, about two years later

Every building permit records the applicant's estimate of what the work will cost. Permits on tax-exempt property, such as Town schools and fire stations, churches and colleges, add no new growth and are left out here. The timing runs on the assessment calendar. Massachusetts values every property as of January 1, a year and a half before the fiscal year that value is taxed in, and new growth is the value added since the previous January 1. So work permitted during 2023 is mostly built during 2023 and 2024, valued on January 1, 2025, and taxed as new growth in FY2026, which began in July 2025.

Lined up that way, a calendar year's permits and the new growth they became track each other closely. From the 2018 to the 2023 permit years, each permitted dollar became 84 cents to $1.21 of new taxable value, 91 cents in the middle year. That alignment fits better than any other tested, including lining permits up by fiscal year (a correlation of 0.55 over 6 years, against well under half that by fiscal year).

So the revenue side of growth is visible about two years ahead, from permits already issued. Single years still swing: the ratio has run from 84 cents to $1.21 per permitted dollar, so permits give new growth within about 20%, not exactly.

The permits already issued point to two weak years. Taxable permits came to $235 million in 2024 and $246 million in 2025, the two lowest years since at least 2018, against $252 million to $378 million a year from 2018 to 2023. Certified new growth also includes business equipment, about an eighth to a sixth of it, which is not built under building permits; set that aside and real estate new growth has come to 0.74 to 1.01 times taxable permits about two years later, in the fiscal year numbered three higher (2024's permits feed FY2027). At the middle rate the 2024 and 2025 permits point to real estate new growth of about $190 million in FY2027 and about $195 million in FY2028. The state has not yet certified either year; FY2026's real estate new growth was $264 million. For FY2027 the base case assumes about $195 million, the Town's budgeted new growth, close to what the permits point to. For FY2028 it assumes about $310 million, more than even the highest past ratio would give. If new growth came in at the permits' level for those two years and then returned to its trend, FY2028 would have $1.3 million less room, a shortfall of about $0.5 million instead of $0.8 million of room, and every later year would carry the shortfall: about $1.7 million less in FY2040. Navigating the next few years sets out what that would do to the budget.

The same timing shows up one property at a time. The Town's assessments of every parcel since FY2009 can be lined up against each property's permits. Of the parcels with one large building permit, $250,000 or more, issued between mid-2017 and 2022, 306 show their value rising clearly faster than the market. For the typical one, about a third of the added value appeared on the first January 1 after the permit and nearly all of it by the second. When in the year the permit was issued matters, because of the January 1 date: 60% of jobs permitted from January to June showed most of their value on the next January 1, and 69% of those permitted from July to December showed it on the one after. For the typical job, half its added value was on the assessment 14 months after the permit, and on the tax bill about six months after that, when the fiscal year began.

The permits recorded before mid-2017 carry no cost, but they do say what the work was. Of the renovations, additions and new buildings permitted from 2008 to mid-2017, 169 show a clear rise, and they took about as long: 12 months to half the added value for the typical job, and 11 to 14 months in each of three periods from 2008 to 2017. Smaller jobs are among them, and more of those reached the first January 1. The timing has held steady for fifteen years. The ratio of value to permitted cost is the part that rests on only six years, because only the newer permits record a cost. Large buildings take longer, and their value can arrive over two or three January assessments (Growth: renovation and what faster growth is worth).

What new homes add, and what renovation adds

New homes are the smaller part of residential new growth. From FY2018 to FY2025, renovation, including houses rebuilt as houses, added about $970 million of it, against about $650 million from the buildings that added homes. And the total has held steady whatever the pace of building: residential new growth has stayed between 0.74% and 1.02% of the levy limit every year since 2009, whether about 40 or about 180 homes a year were being permitted. When fewer homes are built, renovation fills in (Growth: renovation and what faster growth is worth).

What a new home adds depends on its kind. Brookline's permits since 2008 were read one by one and each project followed onto the assessment rolls. Each net new home in an apartment building permitted from 2015 to 2022 added about $521,000 of assessed value, and each in a condominium or small multifamily building about $864,000. The homes the forecast adds, the two in their recent proportions, average about $585,000, about $6,000 a year in tax at the FY2026 rate. A house that adds a home carries the value of the whole new building, several million dollars, which is why houses look so different in a per-home estimate (Counting Brookline's homes).

Costs followed students and births, not homes

Town staff

Every home in Brookline is counted only once a decade, by the Census: 26,448 in 2010 and 27,961 in 2020, 6% more. No yearly count of every home exists for that decade. The Town's assessment rolls have recorded the number of homes on each property only since FY2017, so the homes line before then is the Census trend, which is why it is straight; the chart adds the assessors' count from January 2016. The ten years between the Census counts are still enough to compare.

The assessors' counts since then need cleaning before they can be read as new homes. Their total rose 2,144 from January 2016 to January 2025, but much of that is records rather than building: hotel rooms recorded as homes, a condominium parking lot, and, in one year, the first unit counts for several tax-exempt housing complexes that had stood for decades. Assisted living, which brings no school children, is counted separately. Without those, the rolls show 1,082 more homes over those nine years, about 120 a year, arriving unevenly, from 5 in one year to 273 in another. Brookline's building permits, each read and counted for this project, agree with the rolls: about as many homes reach the roll as were permitted, a year or so later (Counting Brookline's homes).

The permits do not agree with the Census decade. Permits issued from 2009 to 2018, the homes that could have been finished by the 2020 count, add up to about 350 net new homes, far fewer than the Census difference of about 1,500. The gap most likely lies in how the two counts were taken rather than in building nobody permitted, and it does not change the comparison below: by either count, police and fire staffing did not grow with homes.

Over that decade budgeted police and fire positions went from 338 to 341. A project-by-project estimate puts most of a new home's Town cost in police and fire; Brookline's record does not show those costs arriving with homes. Fire staffing is set by stations and companies staffed around the clock, so it changes in steps. The other Town departments went from 338 to 347 positions, then added about 40 from FY2021 to FY2025, to 387. Across all Massachusetts towns, those that added more homes did spend more on their departments, about $660 a year for each added home, well below an average share of the budget (New homes and Brookline's budget). That is the figure the forecast uses.

School staff is where the growth was: from 995 to 1,378, 39% more, as students rose 20%, from 6,472 to 7,777 (the state's count, prekindergarten included). Both grew several times faster than homes. School staff has since come down as enrollment fell. The next two sections ask where the students came from.

Kindergarten followed births, not new construction

Brookline's public school enrollment in kindergarten to grade 12, without prekindergarten, grew from 5,883 in fall 2006 to 7,506 in fall 2019. New construction in those years was modest. Enrollment then fell, to 6,701 in fall 2025, through the years with the most new units authorized since at least 2007: 592 from 2020 to 2025, with 275 in 2022. The pandemic accounts for much of the fall in 2020 and 2021; enrollment has not regained it since.

What moved with enrollment was births. Each fall's kindergarten has been between 0.76 and 1.01 times the births five years earlier since 2006, and kindergarten classes then move up the grades. Outside the pandemic, the number of students moving into or out of grades 1 through 12 in a year has netted to a few dozen, a fraction of one percent of enrollment. The bars count units in new buildings (the Census Bureau's building permit survey). Brookline also adds homes inside existing buildings, through conversions and additions; counting those, its own permits show about 105 net new homes a year since 2016 (Counting Brookline's homes).

Across Massachusetts, added homes bring about half the children of existing ones

One town over fifteen years cannot separate new homes from everything else going on. Comparing 252 Massachusetts cities and towns over the same decade can. Between the 2010 and 2020 Censuses, towns that added more homes kept more of their children, but the relationship is about half as steep as an average-home estimate assumes. Each added home came with about 0.28 more residents under 18 (the range consistent with the data is 0.15 to 0.41); an average existing home had 0.55. Leaving out Boston and weighting towns by size gives 0.30.

Brookline added 1,513 homes over that decade and gained 1,814 children. At the cross-town rate the added homes account for about 420 of them; the rest came from homes that already existed, through births and through families moving in as others moved out. These are children, not students: some attend private school or schools elsewhere, so the effect on enrollment is smaller again.

The same comparison on public school enrollment, for the 196 cities and towns with their own school district, finds a weaker link still. Each added home went with about 0.09 more public school students, with a range from −0.07 to 0.25 that includes no change at all; an average existing home had 0.35. Towns' enrollment moves with births, private and charter school choices and much else, and added homes are a small part of it. The forecast charges 0.24 public school students for each home added beyond the recent pace, the cautious end of that range.

This is a comparison between towns. Towns that add homes differ in other ways, and the result describes the typical added home of the 2010s, much of it apartments and condominiums. It does not say what a particular building will bring.

What others have found about children in new homes

Studies elsewhere point the same way, with some cautions.

• Massachusetts, district by district. The Metropolitan Area Planning Council compared new housing with public school enrollment across Massachusetts districts, first for 2010 to 2016 (2017) and again for 2010 to 2020 using the Census (2024 update). Across 231 districts it found no significant link: in its own region housing grew 7.9% over the decade while enrollment fell 0.3%. The test on this page finds the same.
• Massachusetts, building by building. A UMass study for MassBenchmarks (Rapoza and Goodman, 2019) asked school districts how many students actually lived in 42 new developments with 6,076 homes. Taken together they paid their towns $7.7 million a year more than they cost, about $1,273 a home. But 12 of the 42 cost their town more than they paid, most often where schools were already full or students needed costly special education.
• Brookline itself. A 2007 UMass Donahue Institute study for the Citizens' Housing and Planning Association (report) counted the students in eight mixed-income developments, one of them Kendall Crescent in Brookline: 35 homes, 5 public school students. None of the eight had a measurable effect on the cost of public services, and school costs were rising in towns with falling enrollment as well as rising.
• New Hampshire. A 2024 study for New Hampshire Housing (From Homes to Classrooms) matched students to their home addresses in four towns. Homes built from 2014 to 2023 had 0.16 public school students each, against 0.29 for all housing statewide; new single-family homes had 0.40 and new apartments and condominiums 0.06. The two towns whose new housing was mostly single-family homes came out behind.
• New Jersey. A Rutgers study of about 40,000 rental apartments (2018) found 9.8 school-age children per 100 market-rate apartments built after 2000, against 25.9 in older ones, and about 64 per 100 affordable apartments of either age.
• Newton. The demographer who studies Brookline's enrollment reached the same conclusion for Newton in 2024 (study): growth in households whose children have grown, and the pace of existing home sales, drive enrollment more than new construction.

The cautions run the same way in every study. New apartments and condominiums, especially smaller ones, bring few children; family-sized homes, affordable homes and single-family subdivisions bring more, sometimes as many as existing homes or more; and a town whose schools are full feels each added student more than one with open seats. The Massachusetts building-by-building study is the clearest case: where its developments cost their towns more than they paid, full schools were among the most common reasons.

Where Brookline stands, service by service

Pulling the record together, this is what public budgets and reports suggest about each service. It is a reading from the outside. It has not been checked with the people who run these services, who know things no published figure shows, and the section ends with what it cannot see.

Schools: open seats now, and more coming

The schools were rebuilt and expanded for the enrollment peak of FY2019. Since then enrollment has fallen. On October 1 kindergarten through grade 8 had 4,436 students in 236 classes, with about 1,100 open seats under the School Committee's own class-size guidelines. No grade at any school is over its guideline. The guideline is a ceiling, though. In 2017 the School Department presented an average class of 24 as the outcome to avoid, and this fall's classes average 19. With every class kept three students below its guideline, about 440 seats are open. The fullest schools are Pierce (87%), which moves into its larger new building in fall 2028, and Ruffin Ridley (84%); the emptiest is Hayes (75%). Counting empty classrooms as well as open seats in today's classes, the kindergarten-to-grade-8 buildings, including the new Pierce, have room for roughly 1,000 to 1,700 more students (school seats map). The high school, expanded in 2022, has about 535 seats more than its 2,165 students. In the base case enrollment falls further, to about 5,400 by FY2040, because fewer children are being born to Brookline residents. At the forecast's 0.24 students a home, the seats opening by FY2030 would take about 1,800 homes beyond the recent pace to fill if staff were held at the FY2027 level; with staff falling half as fast as enrollment, as in the base case, about half as many (Schools: staffing, costs and open seats).

Two limits. Seats sit in particular schools and grades, and a large building's children all go to one school's district, so a project near Ruffin Ridley or Pierce uses scarcer room than one near Lincoln. And the open seats could instead be cut, by holding fewer teachers as enrollment falls, as the base case partly does; then students from new homes mean fewer positions cut, and their cost is the saving given up, which is what the project estimate measures.

Fire: companies set by coverage more than by workload

The Fire Department runs five engine companies and two ladder companies from five stations, each staffed with at least four firefighters around the clock, 29 on duty each day. It responds to more than 95% of calls in under four minutes. In FY2025 it made about 10,500 responses, or about 1,500 for each company if each call took one. Fire consultants treat about 3,000 runs a year as the mark of a busy company. Calls bring out more than one company, and the busiest companies, in Brookline Village and Coolidge Corner, run well above the average, so the true figures are higher. Even so, by these measures the average company is well below the usual marks of a busy one, though the busiest may be closer than the average shows.

That is not what decides when a company is added. The standards fire departments are measured against set targets for how quickly the first engine and the full response arrive, which depend on distance, not on the number of homes. The one company the Department has costed, a ladder for South Brookline, is a question of coverage: how quickly a ladder truck reaches the south of town. The Fire Chief would place it at Station 4 on Route 9, which is being rebuilt to house two companies, so the Town could add it in any year, with or without new homes. The forecast's own step, a company once the town reaches 31,200 homes, is the point at which Brookline's firefighters per home would fall to the median of 21 nearby cities and towns. It is a placeholder for when growth alone might call for one, not a measure of capacity, and at the recent pace of building it falls after FY2040.

The pressure on fire today comes from elsewhere. Medical calls rose about 7% a year from FY2021 to FY2025, while homes grew about half a percent a year, most likely because Brookline's population is growing older: residents 65 and over grew 36% from 2010 to 2020. Overtime has run over budget every year since FY2021, by $0.65 million to $2.1 million, which the Town attributes to leave rules in the FY2018 contract and to injured leave up about 150%. Those are costs of the people already here, not of new homes, but they are what would make the Department ask for more firefighters first.

Police: fewer calls, short of its own staffing

Police calls fell from about 75,600 in FY2013 to about 53,000 to 56,000 in FY2024 and FY2025, while homes were added. Part of the fall is a change in how calls were counted, and most of the rest is less activity started by officers themselves, such as traffic stops, while the department ran 14 to 19 officers below its authorized strength; 911 calls rose. So the counts say nothing about new homes adding police work, and they should not be read as falling need either. The budget funds 128 sworn officers; the department's mid-2026 report puts it 18 below its authorized strength. The likelier police cost is filling those positions, a decision about service levels, not about growth. The forecast keeps a small police cost for each new home, $105 a year, rather than a step.

Comparisons of officers per resident are common but a poor test of room. They leave out the commuters, hospital staff, students and shoppers Brookline serves who do not live here, and they measure a town's size rather than how stretched its officers are. Brookline's officers per home are close to the median of nearby towns; that says it is staffed like its peers, not that it has room or lacks it. The measures that would show room, the share of patrol officers' time spent answering calls and how long priority calls wait, are not published.

Other Town departments

The other Town departments, from public works and libraries to general government and human services, added about 40 positions from FY2021 to FY2025, after a decade of holding steady while homes were added. No published measure says whether they have room for more residents. The forecast charges about $660 a year for each new home, less fire's part of about $125, for them and for police, the amount Massachusetts towns that added homes spent on their departments, which is the cautious way to treat a service whose room cannot be measured.

What these measures cannot see

Every figure above comes from budgets, reports and public data. None comes from the people who run the schools, the Fire Department or the Police Department, and none of them has been asked for this page whether they have room. They may well feel stretched now. Services usually strain before any measure of capacity says they are full, and in ways these figures miss:

• People before positions. Overtime, injured and sick leave, vacancies and turnover wear on a department long before its call volume looks high. The Fire Department's overtime and leave and the Police Department's vacancies are signs of strain of that kind, whatever their cause.
• Particular places and hours. A town-wide average hides the busiest company, the busiest shift and the neighborhood farthest from a station. An open seat in one school does not help a full grade in another.
• Space other than classrooms. Rooms for special education, English learners and specialists, cafeterias and gyms can fill before classes reach their size guideline.
• What each student or call needs. A growing share of students with special needs, or of calls that are medical, changes what each seat or call takes.
• Thinner service rather than more cost. Brookline added homes through the 2010s with flat police and fire staffing. That could mean the Town had room, or that service thinned as the same staff covered more residents. The Fire Department's response times, under four minutes for more than 95% of calls, suggest fire service has not thinned town-wide. For police no published reading could tell.

So where each service's limit lies is not known, and this page does not claim to know it. The published readings can show which way things are moving. The rest is a question for the people who run these services.

What to ask the people who run these services

The first question is the simplest: where do they feel stretched now, and what would they expect to need first if the town grew faster? The reading above would also be firmer with five things their departments hold but do not publish:

1. Fire runs by company and response times by station, at the 90th percentile, for 2015 to 2025. These would show which companies are busiest and whether any part of town is losing ground.
2. The 2019 firefighters' union analysis of ladder coverage in South Brookline, cited by the Advisory Committee in 2022 but not posted.
3. Police patrol staffing: the minimum number of officers on each shift, the number of patrol sectors, and the share of patrol time spent on calls, by hour.
4. Police response times to priority calls.
5. School seats by grade at each school, as the School Department projects them each spring, published rather than shared on request.

What to watch

The readings below would show, years ahead in most cases, which way things are moving: whether there is room for new homes, and whether something needs to expand. Where the true thresholds lie is not known. Those marked as this page's own are judgments, not standards, and the people who run each service may well set them differently.

Whether there is room for new homes

Whether something needs to expand

When each reading is in hand, and how closely it has predicted:

So the budget can be seen coming, but not through any single project. Revenue from construction is visible about two years out. Enrollment is visible three to four years out from births and a year out from the grade counts, and it depends on the whole town's births and turnover. Town staffing changes in steps that can be seen approaching as the town's total grows.

What this means for a single project

A project estimate is a fair description of one building's average share. It is a poor guide to what the budget will do where services have room. Revenue from a project arrives on a schedule that can be seen about two years ahead. Its costs do not arrive with it: police and fire have not grown with homes, and school enrollment has moved with births and with turnover in the existing housing far more than with the newest buildings. The useful questions about a project are town-wide ones:

• Is it part of the pace the forecast already counts? The forecast assumes about 105 net new homes a year, mostly apartments and condominiums.
• Does it use scarce room? A family-sized building in the Ruffin Ridley or Pierce district uses fuller schools than one elsewhere.
• Does it bring a step closer? With everything else being built, does it bring the town nearer a fire company or a full grade?

Where the answers are yes, a project estimate's costs become real, and the project that tips a step can carry a large one. Where they are no, the estimate likely overstates the cost, though how close any service is to a step is not something the published figures can settle (Navigating the next few years).

Data and caveats

• The comparison of the two estimates. The 100-apartment example uses the recent value per apartment home, the FY2026 residential tax rate (1.024%), 0.244 students a home, the forecast's $16,975 for an added student with staff and $7,758 for one filling an open seat, RKG Associates' $1,109 a home for Town departments, before benefits, and the forecast's $660 a home plus benefits, less fire's share. The figures mix FY2025 to FY2027 dollars and are rounded; the breakeven test works the same comparison carefully.
• Research on the method. Burchell and Listokin's guidebook, Paulsen (2014) and Kotval and Mullin were read in full; Edwards and Huddleston (2010) and Ladd (1992, 1994) only in their published summaries.
• Fire. Companies, staffing, overtime and the cost of a ladder company from the FY2027 Financial Plan and the Town's FY2024-25 Fire Department overtime and leave memo (revised March 2025). Responses from the Financial Plans' workload tables, with FY2019 to FY2023 filled from the Town's online budget pages. The 3,000-runs mark comes from fire consultants' reports cited in a 2018 U.S. Fire Administration paper; no standard sets a workload at which a company must be added. Runs per company assume one company per call, which understates them.
• Police. Calls from the Financial Plans and the department's annual and mid-year reports, which count calls two different ways over the years; staffing from the FY2027 budget and the 2026 mid-year report.
• Schools. Open seats from the School Department's October 1, 2026 class counts, against the School Committee's class-size guidelines (22 in kindergarten to grade 2, 25 in grades 3 to 8, lower at Pierce and Driscoll); the high school figure is the enrollment the expanded building was designed for.
• Home sales and kindergarten. The School Department's demographic study (2023) expects sales of existing homes, more than new construction, to drive enrollment as households whose children have grown sell to younger ones. Years with more single-family sales have had somewhat more kindergartners per birth (a correlation of 0.48 over 16 years, leaving out fall 2020), but sixteen years is too few to call this proven, condominiums with three or more bedrooms show no such pattern, and in the older grades the students joining or leaving each year have not risen with sales (correlations of -0.28 and -0.42). Sales come from the Town's assessment rolls, FY2009 to FY2026, $100,000 or more; one roll (FY2022) could not be read.
• Business equipment in new growth. The state's certified new growth includes business equipment (personal property), about an eighth to a sixth of it in FY2022 to FY2026 by the Board of Assessors' figures, which is not built under building permits. The chart and the cents per permitted dollar include it; the check on FY2027 and FY2028 sets it aside and compares real estate with real estate.
• Permits and new growth. Town Building Department permit records, calendar 2018 to 2025 (the current system, which starts in mid-2017; the earlier one has no cost field), counted once per permit. The cost is the applicant's own estimate. New growth: Massachusetts Division of Local Services, certified new growth valuation by fiscal year. Six permit years have certified new growth so far, so the fit rests on six points; windows of 12, 24 and 36 months ending at different dates were compared, and this one fit best. The estimated cost is summed over every permit type, so a renovation's building permit and its plumbing, electrical and mechanical permits all count; the ratio is measured on that same total. Counting building permits alone fit no better.
• Timing, property by property. Assessed value of every parcel FY2009 to FY2026, from the Town's assessment rolls, against each parcel's permits, matched by street address. A job's added value is its rise above the median growth of parcels with no permit, through the FY2026 roll (January 1, 2025); a job counts when that rise exceeds 10% of the value before the permit. Newer permits: one building permit of $250,000 or more on the parcel. Older permits (no cost recorded): renovations, additions and new buildings by the permit's description, with no other building permit on the parcel from two years before to four years after.
• Homes on the assessment rolls. Units per parcel, FY2017 to FY2026 rolls. Removed: hotels, a condominium parking lot, private schools, a hospital, tax-exempt residences such as a charity's guest house, one year's recount of lots with more than one house, and any change of 15 or more units on a parcel whose value did not move with it. Assisted living is counted separately. Rolls before FY2017 have no unit field. The FY2026 roll comes from a new records system; its unit count matches the FY2025 roll property by property.
• Staffing and homes. Budgeted positions from the Town's Financial Plans; homes from the 2010 and 2020 Censuses, carried between them at the recent pace, so the homes line is smooth by construction.
• Enrollment. Massachusetts Department of Elementary and Secondary Education, enrollment by grade, October of each school year; resident births from the state's annual birth reports. New units authorized: Census Bureau Building Permits Survey, annual place files, which include the Bureau's estimates for months not reported. The survey counts units in new buildings only.
• Children per added home. Census 2010 and 2020 redistricting counts: residents under 18 and housing units, for the 252 cities and towns with at least 2,000 homes, each town one observation, the growth in children set against the growth in homes. A comparison between towns over one decade, not an experiment.
• Method and code. The code, every series behind this page, and research notes on the fire and police sources, page by page, are in the project's public files on GitHub.

Go deeper

• New homes and Brookline's budget: What does a new home cost the Town, now that enrollment is falling?
• Growth: when a new home pays for itself: When does a new home, or new commercial space, add more tax than it costs the Town?
• Schools: staffing, costs and open seats: How is Brookline's school system staffed, what does an added student cost, and how much room do the schools have?
• Counting Brookline's homes: How many homes has Brookline been adding, of what kind, and what does the forecast assume?
• Enrollment: three forecasts compared: Why do the enrollment forecasts disagree, and which one does the base case use?
• Navigating the next few years: What should Brookline decide in the next few years, and what should it watch while it does?

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