2026 U.S. Senate: Pre-Registered Predictions
July 30, 2026 · five races · two panel tiers · frozen before fielding
Pre-registered before fielding, July 29, 2026: Tier 1 battery frozen in git at 6:08 PM EDT (commit b7c50f3, panel amendment ad9e2c0), fielded 6:11\u20136:14 PM. Tier 2 frozen at 6:42 PM (979867c), fielded 6:42\u20136:44 PM. Resolves against certified results November 3, 2026.
Five Senate races that will decide the majority, fielded in two tiers. Tier 1 (GA, OH, TX): statewide live panels of ~20,600 simulated residents per state with persistent memory, daily news injection, and regional training corpus, n=1,000 per state. Tier 2 (NC, ME): census-weighted agents generated from ACS regional frames and relabeled to the state \u2014 no memory, no news layer, party mix from regional rather than state priors. Tier 2 is the weaker instrument and is labeled directional; publishing both tiers against the same resolution date is a deliberate test of how much the live-panel infrastructure adds.
Same scoring everywhere: first-token logprobs and Dirichlet electoral calibration, as in Issues 01\u201302. Raw and calibrated toplines published together with 95% bootstrap intervals. Michigan is excluded until its August 4 primary resolves \u2014 pre-registering a hypothetical matchup would weaken the exercise.
Synthetic calibrated panels \u2014 not probability samples. No humans were interviewed.
Georgia
Tier 1 · Live panelGeorgia statewide live panel · n=1,000 of 20,638
Jon Ossoff (D) vs Mike Collins (R)
Ossoff +11.5 · Dem share 55.7% calibrated (95% CI 53.3–58.1) · 57.3% raw
- Jon Ossoff55.7% (raw 57.3%)
- Mike Collins44.2% (raw 40.6%)
- Undecided0.1% (raw 2.2%)
Recent public polls: Wick (Jun 27–30) Ossoff +4; Beacon/Shaw (Jun 23–27) Ossoff +13; Echelon (Apr) Ossoff +7. Our read sits inside the recent poll range, at the high end.
Ohio
Tier 1 · Live panelOhio statewide live panel · n=1,000 of 20,638
Sherrod Brown (D) vs Jon Husted (R) — special election
Brown +18.4 · Dem share 59.1% calibrated (95% CI 57.0–61.8) · 60.3% raw
- Sherrod Brown (D)59.1% (raw 60.3%)
- Jon Husted (R)40.7% (raw 36.4%)
- Undecided0.1% (raw 3.3%)
Polling averages (early Jul): Brown +1.3 (270toWin), +1.5 (DDHQ). Our panel is far more bullish on Brown than human polls — driven by independents breaking 86/5 for Brown. Pre-registered as-is; November decides.
Texas
Tier 1 · Live panelTexas statewide live panel · n=1,000 of 20,637
James Talarico (D) vs Ken Paxton (R)
Paxton +10.7 · Dem share 44.6% calibrated (95% CI 42.3–46.6) · 43.7% raw
- James Talarico44.6% (raw 43.7%)
- Ken Paxton55.3% (raw 54.8%)
- Undecided0.1% (raw 1.6%)
Polling averages (Jul): Talarico +0.4 — a tossup (NYT/Siena Jun: tied 47/47). Our panel is far more bullish on Paxton than human polls. Pre-registered as-is; November decides.
North Carolina
Tier 2 · DirectionalCensus-generated agents (ACS South frame, state-relabeled) · n=1,000 generated
Roy Cooper (D) vs Michael Whatley (R) — open seat
Cooper +3.3 · Dem share 51.6% calibrated (95% CI 49.2–54.1) · 52.3% raw
- Roy Cooper51.6% (raw 52.3%)
- Michael Whatley48.3% (raw 45.7%)
- Undecided0.1% (raw 2%)
Polling averages (mid-Jul): Cooper +8.4; PPP (Jul 10–11) Cooper +4. Our directional read is tighter than the polling average.
Maine
Tier 2 · DirectionalCensus-generated agents (ACS Northeast frame, state-relabeled) · n=1,000 generated
Troy Jackson (D) vs Susan Collins (R)
Collins +31.9 · Dem share 34.0% calibrated (95% CI 32.1–35.9) · 29.9% raw
- Troy Jackson34% (raw 29.9%)
- Susan Collins65.9% (raw 68.3%)
- Undecided0.1% (raw 1.8%)
No public poll of this matchup existed at pre-registration — Jackson became the nominee July 25 after Platner withdrew. The panel gives Collins heavy crossover: 25% of panel Democrats and 88% of independents pick her. Collins outperformed her polls by ~9 points in 2020; November decides whether this read or the fundamentals-based skepticism is right.
Where we differ from human polls
Our Ohio read is well to the left of the polling average (Brown +18.4 vs +1.3), our Texas read is well to the right of it (Paxton +10.7 vs a Talarico +0.4 tossup), and our Maine read gives Collins a landslide no fundamentals model would print. North Carolina and Georgia sit near the polls. The divergences run in both directions, so this is not a uniform partisan lean \u2014 it is a different signal. Partisans vote their party at 92\u201399% in every state (Maine is the exception by design of the read: 25% of panel Democrats cross to Collins); the rest of the differences come from how independents break. If the panel is wrong, the scorecard will say so in November.
Known instrument effect: the panel allocates far less mass to \u201cUndecided\u201d (0.1\u20133% raw) than human polls do (4\u201310%). Two-way vote share is the primary pre-registered metric.
Data downloads
Per-respondent probability distributions (n=5,000) available to researchers on request.