One data source lies to you roughly 1% of the time — stale quotes, broken fields, frozen fundamentals. At that rate, a single bad data point every few days is guaranteed. AI Stock Monitor does not trust any single source for critical numbers. Instead, it polls multiple sources and votes on the answer. This article explains how the vote works and why you should care.

The Voting Rule in One Sentence

For every number that matters — price, P/E, dividend yield, implied volatility — the system asks 2 or more sources independently, throws out garbage values, and takes the median of the majority cluster. Outliers are flagged in the data trail rather than silently averaged away.

3/3 agree
Full consensus
All sources within tolerance. The vote is boring. You get the clean number with no downgrade notice. This is the common case.
2/3 agree
One source is off
Two sources cluster, one disagrees. The outlier is discarded; the majority median is used. The UI shows a small "1 source dissented" note so you know.
1 source
Data downgrade
Only one source has the field. No voting possible — the number is displayed with a visible "downgraded" badge. Treat with caution.

Why Not Just Trust the "Best" Source?

Every source has known failure modes:

  • Polygon: great for US equities, returns 404 for most non-US listings (e.g. UK .L suffix).
  • yfinance: broad coverage but notorious for stale or frozen fundamentals — yesterday's number served as today's.
  • IBKR: most authoritative when your market-data subscription covers the exchange, but silent otherwise.
  • Tradier: reliable for US options, unavailable elsewhere.

"Trust the best source" works until the best source is the one that's broken today. Voting catches that — the discrepancy is the signal that something is wrong, and you see it before you act on the bad number.

The most dangerous data bugs are the ones that do not look like bugs — a reasonable-looking number served from a frozen cache. Voting surfaces these, because a frozen source rarely matches two live ones.

Where You See the Vote

Every fundamentals card and IV card in the app shows a small source-count badge. On a clean vote you see nothing extra — the number just is. On an outlier, you see "2/3 · 1 outlier". On a downgrade, you see "1 source · downgraded" in amber. That badge is your tell for how much to trust the specific number.

Single source = single point of silent failure
2+ sources · majority-cluster median · outliers flagged
Look for the source badge before you act on any key number

Open your dashboard →