OH-15 · House

The district, in brief

Ohio's 15th sits in the Columbus metro area, taking in the western, southern and some northern suburbs of Columbus, including Dublin, Hilliard and Grove City. The facts on file mark the district as redrawn for 2026, on a map first used this cycle; the text does not describe how the lines changed and gives no presidential result for the district.

The incumbent is Republican Mike Carey, re-elected with 56.5% of the vote in 2024. He faced Samuel Ronan in the Republican primary; the text's results table for that primary is missing. The Democratic nominee is Don Leonard, who won his primary with 52.9% over Adam Miller, a former state representative and the party's 2024 nominee, though Miller had outraised him $779,132 to $261,394 as of March 31, 2026. The text gives no background for Leonard. Libertarian Brennan Barrington is also on the ballot. As of June 30, 2026 Carey had raised $3,299,678 with $2,056,712 on hand, against $606,657 raised and $252,401 on hand for Leonard.

Every rater listed calls the seat R: Decision Desk HQ (July 14, 2026), the Cook Political Report (August 13, 2026), Inside Elections (October 31, 2025), Sabato's Crystal Ball (September 29, 2026) and The Economist (April 24, 2026). Three district polls, all from Hart Research, a Democratic firm, are recorded: September 22–24, 2026 (500 LV) had Leonard 46%, Carey 45%, undecided 9%; August 6–9 (401 LV) had Carey 41%, Leonard 37%, Barrington 10%; June 23–25 (550 LV) had Carey 45%, Leonard 40%, Barrington 3%. A June generic test from the same firm had a generic Democrat at 47% and a generic Republican at 44%.

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: The text is garbled: the district description's opening and the Republican primary results table are missing, and the Democratic nominee's own line (background) is absent.; The text gives no presidential results for the district on any lines.; The text does not say how the 2026 map changed the district, only that the facts mark it as redrawn.; The three district polls are on Wikipedia but the model's basis records no district polls; all are from one Democratic-aligned pollster.; No general-election ratings finer than 'R' are given.

Read from the district's section of Wikipedia's state page (CC BY-SA), archived as 568e9f52653f; 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.

Who holds the seat now

Mike Carey (Republican), in this chamber since 2021, 3 terms. Committees: Joint Committee of Congress on the Library; House Committee on Ways and Means; House Committee on the Budget; House Committee on House Administration.

From the congress-legislators dataset (CC0), archived as ae8cb9477c48. For a Senate race this lists both of the state's senators; the one whose term ends in the election year holds the seat on the ballot. For a House district redrawn for 2026 it is the member elected under the old lines with this number, who may be running elsewhere; the dossier above names who is running here.

How it has voted for president

A shift of 1.9 points toward the Republicans from 2016 to 2024. county returns placed on the current lines by 2020 block population; 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.

Who are the voters?

Of about 533,741 adults 25 and over. In 2020 the district voted 46.2% Democratic (two-party) for president. With the same preferences and a 2022-style midterm turnout, it would vote 46.2% Democratic: the midterm electorate alone moves the margin 0.1 points toward Republicans. Group shares are estimated from how results vary across the state's census tracts (ecological inference, anchored to Pew's 2020 validated-voter figures) and calibrated to this district's actual 2020 vote; turnout is the Census survey's state rate by race and national rate by education, whose state samples carry margins of several points.

Not answered here: how each group will vote in 2026. These are 2020 preferences; this profile is description, not yet an input to the forecast.

The money

FEC bulk candidate summaries through June 30, 2026; $9,012 of independent expenditures for or against these candidates this cycle (FEC Schedule E, types 24E and 24A), which is the parties' and outside groups' own revealed view of whether this seat is in play.

The district in numbers

ACS 5-year 2023, assembled from census tracts by the 2020 population of their blocks inside the current lines, because the Bureau has not tabulated these lines; medians are population-weighted means of tract medians. Unemployment is the BLS county series placed on the district by block population, not seasonally adjusted, so changes are same-month comparisons. Income, transfers and jobs are BEA county accounts placed the same way, compared with the average district. Every other figure is a named column of a named table in the Bureau's summary file, archived before it was read. This is what a reader knows about a district before looking at a poll; the model does not yet use it, and whether it should is a registered question.

Who is favoured, and by how much?

The 90% interval runs from -11.7 to +18.4 points, D-R. It is wide because this district has never been polled.

What is this built on?

A model trained on every contested House race 2012-2024 predicts this district's lean from its own record: presidential and House results on the current lines, incumbency, both candidates' prior offices, outside and party money before 1 October, demographics and public-assistance shares from the Census release before the election, local unemployment and income, and religious tradition. The national margin comes from presidential approval, the economy, the midterm penalty and the generic ballot corrected for its measured lean. Draws share national and state errors, so the seat total and this district come from the same simulation.

Not answered here: district polls, which are not yet folded in.

Why does the model say this?

Each figure is how far this district's predicted lean moves when that one feature is set to the typical value across 2026 districts, everything else held: 2024 presidential lean (D+4.3): 7.5 pts toward the Democrat; experience gap (-4 levels, D minus R): 7.0 pts toward the Republican; outside money balance: 1.2 pts toward the Democrat; PAC money balance: 1.0 pts toward the Republican; moved from other state share (1.9%): 0.7 pts toward the Republican.

How sure is it, and of what?

Total sd 9.18 points, made of the seat's own volatility 91%, correlated polling error 9%. The decomposition is stored with the forecast rather than reconstructed, so a probability whose dominant input is a placeholder is visibly that.

Not answered here: a nowcast. 'If ballots were cast today' needs something that observes today, and for a House district nothing does. Publishing the election-day figure under both labels would make one forecast look like two.

How was this number made?

Run 00a09d4b-7980-4ec5-ada0-077968a87242, house_district_prior/0.2.0, as of 2026-10-02. Promoted by a pre-registered gate: on 2016-2022 its Brier score was 0.036 against 0.049 for the previous method, and on a single 2024 run 0.023 against 0.032 (experiments/district_gate_result.md, with an independent review).