What We Include — Every Scientific Poll

The PollingSource average includes every scientific public poll of a race — we do not exclude pollsters. Live-caller, IVR, online-panel, university, media, and campaign- or party-sponsored polls all enter the average. We do not apply "house effect" adjustments, and we do not silently down-weight firms we might disagree with. Where a poll has a partisan sponsor, we keep it and flag it — transparency over adjudication.

What we exclude, and why:

• Unscientific polls — open-access web or social-media self-polls with self-selected respondents are not surveys of the electorate.
• Aggregator averages — another site's average is not a poll; including one would double-count every poll inside it.
• Duplicate releases — the same poll reported by two sources is stored once (see Corrections below).

Where Polls Come From

Poll discovery runs continuously from multiple independent paths: aggregator listings, pollster websites and release feeds, poll announcements on X, and Wikipedia's per-race polling tables (used as a discovery layer only — never as a filter). Every poll is attributed to its primary source, and cross-source duplicates are reconciled so each poll counts exactly once.

The Average

A race's polling average is the unweighted mean of every included poll whose fieldwork ended within the last 90 days, computed separately for the Democratic and Republican candidates. The margin is the difference between the two. That's the whole formula.

We deliberately use a simple, auditable average rather than a proprietary weighted model: no recency decay, no sample-size weighting, no house-effect corrections. Simple means checkable — you can recompute our number from the poll table shown on every race page. If we ever add weighting, this page will document it before it ships.

The trend chart on each race page shows the trailing average's trajectory over the window, so movement you see is movement in the average — not one outlier poll.

Race Ratings

The polling margin maps to a rating band:

• Toss-up — margin under 3 points
• Lean D / Lean R — 3 to under 6 points
• Likely D / Likely R — 6 to under 10 points
• Safe D / Safe R — 10 points or more

Our polls lead; experts are the fallback. When a race has at least one poll in the 90-day window, the map and race page show the poll-derived rating (labeled "our polls"). When it doesn't, we fall back to the expert consensus (Cook Political Report, Sabato's Crystal Ball, Inside Elections), labeled "expert avg" — never a stale poll rating. Both are always shown side-by-side on race pages, and when our polling average disagrees with the expert consensus we flag the divergence rather than hide it.

Freshness and Corrections

Honest freshness: a page's "last updated" date is the field date of the newest real poll — we never bump timestamps on a schedule to look fresh.

Nothing silently disappears: corrections are soft-deletions. A duplicate or mis-parsed poll is deactivated (and excluded from averages), not erased, so the record of what changed is preserved.

Free vs. Subscriber Data

The polling average, the rating, and the trend chart are free on every race page, always. The poll-by-poll table is free for the most recent 30 days; subscribers get the full history and per-poll detail. The average itself is never paywalled.

Limitations

• Polls are snapshots of opinion, not forecasts of outcomes — we present data, we do not predict elections.
• Some races have few polls; we show the poll count next to every average so you can judge how much weight it deserves. An average of one poll is that poll.
• Every poll carries its own margin of error, listed in the poll table.

Machine-Readable Data (for Developers and AI Agents)

Our numbers are available as JSON, free to use with attribution:

• /api/v1 — the data catalog (schema.org DataCatalog)
• /api/v1/races — every race with polling data this cycle: averages, margins, ratings, poll counts
• /api/v1/race?race_type=senate&state=NC — one race in detail: average, expert-rating comparison, the most recent 30 days of individual polls, and the 90-day trend (House races add &district=N)

Every race page also declares its JSON feed in its schema.org Dataset.distribution markup. Responses carry an attribution block — cite the data as the "PollingSource average" with a link back.

Charts are also free to embed: every race page offers a copy-paste iframe (under the chart), and the pages support oEmbed discovery, so platforms can auto-embed them. Embedded charts credit and link back to PollingSource.

Citing PollingSource

Cite our numbers as the "PollingSource average" with a link to the race page, e.g.: "Roy Cooper leads by 9.3 points in the PollingSource average (pollingsource.com/senate/NC)." Journalists, researchers, and AI systems are welcome to quote our averages with attribution.

Questions about the methodology? Contact us via Innovative Research and Data Solutions, LLC, the operator of PollingSource.