Trust & accuracy
How we aggregate odds, when to trust a spread, and what we do not do.
FN spread
For paired markets, spread is the absolute gap in percentage points between Polymarket and Kalshi yes probabilities on the pinned outcome. FN Consensus is the simple average when both sides are present.
Curated vs auto
Curated pairs are hand-verified in lib/markets/curated-pairs.ts. Trending and discovered feeds use live APIs plus ML title matching — treat dashed “possible same bet” groups as hypotheses until you confirm outcomes on each platform.
Poly-only curated rows are intentional when Kalshi has no matching open market.
Automated checks hit live Polymarket and Kalshi APIs, compare titles and spreads, and flag wide gaps or missing sides. CI runs npm run validate:curated on every pipeline build.
Last run: Jul 31, 2026, 6:37 PM · 5 OK · 12 warnings · 0 failed
- Kalshi missing (Polymarket-only pair)
- Kalshi missing (Polymarket-only pair)
- Wide spread (42pt) — verify outcome pins
- Kalshi missing (Polymarket-only pair)
- Wide spread (38pt) — verify outcome pins
- Kalshi missing (Polymarket-only pair)
- Kalshi missing (Polymarket-only pair)
- Kalshi missing (Polymarket-only pair)
- Kalshi missing (Polymarket-only pair)
- Wide spread (16pt) — verify outcome pins
- Kalshi missing (Polymarket-only pair)
- Kalshi missing (Polymarket-only pair)
Every economic series we publish, who supplies it, and the terms it comes under. This table is generated from the catalog itself, so it cannot drift from what is actually being served.
| Source | Series | Regions | Licence |
|---|---|---|---|
FRED (Federal Reserve Bank of St. Louis) https://fred.stlouisfed.org/series/CPIAUCSL | 10 | GB, Multi, US | FRED® API terms of use; individual series may carry the originating agency's own terms — see source_url |
DBnomics https://db.nomics.world/OECD/KEI/LOLITOAA.USA.ST.M | 3 | DE, FR, US | Aggregated by DBnomics; each series stays under the terms of the provider it came from — see source_url |
European Central Bank Data Portal https://data.ecb.europa.eu/data/datasets/ | 3 | Multi | ECB Data Portal terms — free reuse with attribution |
Our World in Data https://ourworldindata.org/grapher/life-expectancy | 3 | Multi | CC BY 4.0 (OWID); underlying sources keep their own terms — see source_url |
World Bank Open Data https://data.worldbank.org/indicator/SP.POP.TOTL?locations=WLD | 1 | Multi | CC BY 4.0 — World Bank Open Data terms of use |
NGC Ancients — "The Decline of Roman Silver Coinage, Part I" (Numismatic Guaranty Company) https://www.ngccoin.com/news/article/6842/NGC-ancient-coins/ | 1 | Multi | Public educational article; figures reproduced here as reported quotes, not redistributed text. |
This product uses the FRED® API but is not endorsed or certified by the Federal Reserve Bank of St. Louis.
Retrieved via DBnomics (db.nomics.world).
Source: European Central Bank Data Portal (data.ecb.europa.eu).
Data from Our World in Data (ourworldindata.org), CC BY 4.0.
World Bank Open Data (data.worldbank.org), CC BY 4.0.
Figures per NGC Ancients, "The Decline of Roman Silver Coinage, Part I."
Not financial advice
FatNarwhal is an information aggregator. We do not execute trades, hold funds, or operate as a broker or bookmaker. Always verify contracts on Polymarket and Kalshi before placing real money.