Massachusetts · Governor

Who is running?

Maura Healey (Democratic), Michael Minogue (Republican), Andrea James (Independent). The margin below is Maura Healey minus the other candidate in the main contest; the rest are on the ballot and not in it.

The race, in brief

Massachusetts elects its governor on November 3, 2026. The state profile records a college share of 0.5, a foreign-born share of 0.2 and a median age of 40.0.

Democratic incumbent Maura Healey, governor since 2023, seeks a second term with Lieutenant Governor Kim Driscoll; she took 98.3% in the September 1 primary. The Republican nominee is Michael Minogue, former CEO of Abiomed, who won 70.4% at the April 25 convention and 75.6% in the primary over Brian Shortsleeve. His running mate is Shawn Oliver, who had run with Shortsleeve; the convention's choice, Anne Brensley, was disqualified. An independent, Andrea James, has also declared.

Every rater listed calls the race D, with dates from September 4, 2025 to September 23, 2026. Recent polls: MassINC Polling Group (September 14–22, 2026) had Healey 51%, Minogue 30%; the University of New Hampshire (September 17–21) Healey 54%, Minogue 38%. The text's polling average is Healey 54.3%, Minogue 34.3%.

A paragraph quoting a model forecast from the day this brief was written is omitted; the current forecast is at the top of this page.

The facts, each beside its sentence

Not in the source: No fundraising figures appear in the text.; No 2022 result or presidential results for Massachusetts are given.; facts.candidates marks Healey as incumbent: false, but the text names her the Democratic incumbent.; The forecast rows carry no basis field, so the text cannot say whether the model uses the statewide polls listed here.

Read from the district's section of Wikipedia's state page (CC BY-SA), archived as 4d76ff0df251; written by claude-fable-5-1 (batch reader) on 2026-09-30 and checked mechanically: every quote occurs verbatim in the archived text, every number in the brief occurs in the inputs. No probability here is the reader's.

How it has voted for president

A shift of 3.4 points toward the Republicans from 2016 to 2024. county returns summed; MEDSL county file (2016), an MIT-licensed county file (2020, checked against certified state results) and MEDSL precinct returns (2024). For a district split across counties this is an estimate, and where the state published the exact 2024 figure for these lines, that exact figure is the one the model uses.

The state in numbers

ACS 5-year state tables; BLS county unemployment and BEA county income, transfers and jobs summed to the state. Every figure is a named column of a named public-domain table, archived before it was read.

Who is ahead, and by how much?

Two numbers because they answer two questions. The nowcast is where opinion stands; the election-day forecast is where it is likely to end up.

How likely is each to win?

Monte Carlo error is ±0.0 points. A change smaller than that is simulation noise rather than news, and this page will not describe it as movement.

How wide is the range?

Nowcast: 90% of simulations fall between +11.8 and +31.3 points. Election day: +11.0 to +34.3. The election-day interval is 3.8 points wider, which is the 33 days of movement still to come.

What is the uncertainty made of?

Total sd 7.37 points, made of race-specific polling error 46%, drift to election day 30%, latent opinion 14%, correlated polling error 11%. The decomposition is stored with the forecast rather than reconstructed, so a probability whose dominant input is a placeholder is visibly that.

What evidence is this built on?

9 polls, most recent 2026-09-21. every input is provisional.

What changed since the last run?

Shaded band is the 90% interval, line is the central estimate, positive is Maura Healey ahead of Andrea James. Over 15 stored forecasts the central estimate moved +0.9 points. There were 7 specification changes (marked on the axis) and no new polls arrived over this window — so every movement in this chart is a change to the model, not a change in the race.

Since 2026-10-01: margin +0.00 points, win probability +0.0 points, on +0 polls.

Not answered here: why it changed. Splitting a move into new polls, time and specification means re-running the earlier model against the later inputs -- two extra posterior fits -- so it is computed on a cadence (scripts/attribute_forecasts.py) rather than while you wait. This pair of runs has not been decomposed yet. The size of the move is shown; the cause is not guessed at.

How has this model done before?

Measured on 230 forecasts across 230 races in cycles 2016,2018,2020,2022,2024: mean absolute error 4.56 points, Brier score 0.0543. The nominal 90% interval contained the result 94% of the time, the 80% interval 84%, and the 50% interval 47%. Read that with care: a national polling miss moves every race in a cycle at once, so the sample size for a question about the intervals is 5 cycle(s), not 230 forecasts. Per cycle -- bias +1.644 pts; 2016: n=43 bias=+4.68 cov90=0.860; 2018: n=63 bias=-0.52 cov90=1.000; 2020: n=35 bias=+5.44 cov90=0.886; 2022: n=54 bias=-0.60 cov90=0.944; 2024: n=35 bias=+1.48 cov90=1.000.

Where did every number come from?

Nowcast run 955ebfba-21a4-453b-9b5d-47964bfc14bf and election-day run 1b06363b-2551-4eef-8063-b19ffd8cd0be, model single_race_latent/0.8.1 at commit bdf7e83107c17a2399efe61a44ef1bbee48f9284, seeds 20260924 and 20260924.